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Immunotherapy Side Effects: What to Watch For and When to Call

Immunotherapy can feel like a hopeful new chapter, and it's natural to wonder what it will feel like day to day. These drugs work by taking the brakes off your immune system so it can find cancer. Sometimes that stronger immune system also bothers healthy parts of the body. The good news is that most of these side effects are treatable, especially when they're caught early, and you and your loved ones are a big part of catching them.

ℹ️ General information to help you and your loved ones talk with your care team, not medical advice. Read our disclaimer.

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The short version

These are called immune-related adverse events (immune side effects). They can affect almost any organ, most often the skin, bowel, hormone glands, lungs, and liver.
They can start any time, from the first weeks to months after your last dose.
Combining two immunotherapy drugs, for example, Opdivo (nivolumab) with Yervoy (ipilimumab), raises the chance of side effects.
Early reporting matters. Call your team about anything new, even if it seems small.

Which drugs are immunotherapy?

This guide covers immune checkpoint inhibitors, the most common kind of immunotherapy. If your drug is on this list, the side effects below apply to you. Doctors and nurses often use short nicknames, so we've listed those too, to help you match what you hear in clinic. All of these are FDA-approved in the US as of October 2026. To see which ones are approved for your cancer, jump to immunotherapy approved for each cancer.

Type	Brand (generic)	How it's given	Nickname you may hear
PD-1 blockers	Keytruda (pembrolizumab)	IV infusion	pembro
	Keytruda Qlex (pembrolizumab and berahyaluronidase alfa)	Shot under the skin	pembro sub-Q
	Opdivo (nivolumab)	IV infusion	nivo
	Opdivo Qvantig (nivolumab and hyaluronidase)	Shot under the skin	nivo sub-Q
	Libtayo (cemiplimab)	IV infusion	—
	Jemperli (dostarlimab)	IV infusion	dostar
	Loqtorzi (toripalimab)	IV infusion	—
	Tevimbra (tislelizumab)	IV infusion	tisle
	Zynyz (retifanlimab)	IV infusion	retifan
	Penpulimab (penpulimab-kcqx; no brand name)	IV infusion	—
PD-L1 blockers	Tecentriq (atezolizumab)	IV infusion	atezo
	Tecentriq Hybreza (atezolizumab and hyaluronidase)	Shot under the skin	atezo sub-Q
	Imfinzi (durvalumab)	IV infusion	durva
	Bavencio (avelumab)	IV infusion	—
	Unloxcyt (cosibelimab)	IV infusion	—
CTLA-4 blockers	Yervoy (ipilimumab)	IV infusion	ipi
CTLA-4 blockers	Imjudo (tremelimumab)	IV infusion	—
LAG-3 plus PD-1 combination	Opdualag (nivolumab and relatlimab)	IV infusion	nivo-rela

Some people get two of these together, for example, Opdivo (nivolumab) with Yervoy (ipilimumab), often called "nivo-ipi," or Imfinzi (durvalumab) with Imjudo (tremelimumab). The shots under the skin contain the same medicine as the IV version, so the side effects are the same.

Other kinds of immunotherapy, such as CAR T-cell therapy and bispecific antibodies, for example, Imdelltra (tarlatamab), work differently and can cause other side effects, such as cytokine release syndrome (a fever and flu-like reaction). Ask your team which kind you're getting.

Immunotherapy approved for each cancer

Here is every FDA-approved use of immunotherapy for the cancers we cover, as written in each drug's FDA label as of October 23, 2026. Your exact situation, such as stage, earlier treatment, and test results, decides which ones fit, so use this list to start a conversation with your care team.

A few terms: PD-L1 TPS or CPS is a score from a lab test on your tumor. MSI-H or dMMR means the tumor can't fix certain DNA errors. TMB-H means the tumor has many gene changes. The "or Qlex," "or Qvantig," and "or Hybreza" versions are shots under the skin with the same medicine.

Non-small cell lung cancer (NSCLC)

Brand (generic)	What it's approved for	When in treatment	Test result needed	Given with
Keytruda (pembrolizumab) or Keytruda Qlex	Lung cancer that can be removed with surgery (tumor at least 4 cm, or in lymph nodes)	Before surgery, then continued alone after surgery	None required	Platinum chemo before surgery
Keytruda (pembrolizumab) or Keytruda Qlex	Stage IB (tumor at least 4 cm), II, or IIIA lung cancer after surgery	After surgery and platinum chemo, to lower the chance of it coming back	None required	Given alone
Keytruda (pembrolizumab) or Keytruda Qlex	Stage III lung cancer that can't be treated with surgery or chemoradiation, or cancer that has spread	First treatment	PD-L1 TPS of 1% or higher, and no EGFR or ALK changes	Given alone
Keytruda (pembrolizumab) or Keytruda Qlex	Nonsquamous lung cancer that has spread	First treatment	No EGFR or ALK changes	Pemetrexed and platinum chemo
Keytruda (pembrolizumab) or Keytruda Qlex	Squamous lung cancer that has spread	First treatment	None required	Carboplatin and either paclitaxel or nab-paclitaxel (Abraxane)
Keytruda (pembrolizumab) or Keytruda Qlex	Lung cancer that has spread and grew during or after platinum chemo	Later treatment	PD-L1 TPS of 1% or higher. People with EGFR or ALK changes should first have tried an approved targeted drug	Given alone
Opdivo (nivolumab) or Opdivo Qvantig	Lung cancer that can be removed with surgery (tumor at least 4 cm, or in lymph nodes)	Before surgery only	None required	Platinum-doublet chemo
Opdivo (nivolumab) or Opdivo Qvantig	Lung cancer that can be removed with surgery (tumor at least 4 cm, or in lymph nodes)	Before surgery, then continued alone after surgery	No EGFR or ALK changes	Platinum-doublet chemo before surgery
Opdivo (nivolumab) plus Yervoy (ipilimumab)	Lung cancer that has spread	First treatment	PD-L1 of 1% or higher, and no EGFR or ALK changes	Each other (IV Opdivo only)
Opdivo (nivolumab) plus Yervoy (ipilimumab)	Lung cancer that has spread or come back	First treatment	No EGFR or ALK changes	Each other, plus 2 cycles of platinum-doublet chemo (IV Opdivo only)
Opdivo (nivolumab) or Opdivo Qvantig	Lung cancer that has spread and grew during or after platinum chemo	Later treatment	None required. People with EGFR or ALK changes should first have tried an approved targeted drug	Given alone
Tecentriq (atezolizumab) or Tecentriq Hybreza	Stage II to IIIA lung cancer after surgery	After surgery and platinum chemo	PD-L1 on 1% or more of tumor cells	Given alone
Tecentriq (atezolizumab) or Tecentriq Hybreza	Lung cancer that has spread	First treatment	High PD-L1 (50% or more of tumor cells, or immune cells covering 10% or more of the tumor), and no EGFR or ALK changes	Given alone
Tecentriq (atezolizumab) or Tecentriq Hybreza	Nonsquamous lung cancer that has spread	First treatment	No EGFR or ALK changes	Bevacizumab (Avastin), paclitaxel, and carboplatin
Tecentriq (atezolizumab) or Tecentriq Hybreza	Nonsquamous lung cancer that has spread	First treatment	No EGFR or ALK changes	Nab-paclitaxel (Abraxane) and carboplatin
Tecentriq (atezolizumab) or Tecentriq Hybreza	Lung cancer that has spread and grew during or after platinum chemo	Later treatment	None required. People with EGFR or ALK changes should first have tried an approved targeted drug	Given alone
Imfinzi (durvalumab)	Lung cancer that can be removed with surgery (tumor at least 4 cm, or in lymph nodes)	Before surgery, then continued alone after surgery	No known EGFR mutation or ALK rearrangement	Platinum chemo before surgery
Imfinzi (durvalumab)	Stage III lung cancer that can't be removed with surgery	After chemoradiation (chemo and radiation together), if the cancer hasn't grown	None required	Given alone
Imfinzi (durvalumab) plus Imjudo (tremelimumab)	Lung cancer that has spread	First treatment	No sensitizing EGFR mutation or ALK change	Each other, plus platinum chemo
Libtayo (cemiplimab)	Locally advanced lung cancer that can't be treated with surgery or chemoradiation, or cancer that has spread	First treatment	No EGFR, ALK, or ROS1 changes	Platinum chemo
Libtayo (cemiplimab)	Locally advanced lung cancer that can't be treated with surgery or chemoradiation, or cancer that has spread	First treatment	High PD-L1 (TPS of 50% or higher), and no EGFR, ALK, or ROS1 changes	Given alone

FDA labels on DailyMed: Keytruda, Keytruda Qlex, Opdivo, Opdivo Qvantig, Yervoy, Tecentriq, Tecentriq Hybreza, Imfinzi, Imjudo, Libtayo. Tumor-agnostic approvals below can also apply.

Small cell lung cancer (SCLC)

Brand (generic)	What it's approved for	When in treatment	Test result needed	Given with
Imfinzi (durvalumab)	Limited-stage small cell lung cancer	After chemoradiation, if the cancer hasn't grown	None required	Given alone
Imfinzi (durvalumab)	Extensive-stage small cell lung cancer	First treatment	None required	Etoposide and either carboplatin or cisplatin
Tecentriq (atezolizumab) or Tecentriq Hybreza	Extensive-stage small cell lung cancer	First treatment	None required	Carboplatin and etoposide
Tecentriq (atezolizumab) or Tecentriq Hybreza	Extensive-stage small cell lung cancer that hasn't grown after first treatment with atezolizumab, carboplatin, and etoposide	Maintenance (keeping it in check)	None required	Lurbinectedin (Zepzelca)
Imdelltra (tarlatamab)	Extensive-stage small cell lung cancer that grew during or after platinum chemo	Later treatment	None required	Given alone. This is a bispecific T-cell engager, a different kind of immunotherapy

FDA labels on DailyMed: Imfinzi, Tecentriq, Tecentriq Hybreza, Imdelltra. Tumor-agnostic approvals below can also apply.

Breast cancer

Brand (generic)	What it's approved for	When in treatment	Test result needed	Given with
Keytruda (pembrolizumab) or Keytruda Qlex	High-risk early-stage triple-negative breast cancer (TNBC)	Before surgery, then continued alone after surgery	None required	Chemo before surgery
Keytruda (pembrolizumab) or Keytruda Qlex	Triple-negative breast cancer that can't be removed with surgery or has spread	First treatment	PD-L1 CPS of 10 or higher	Trodelvy (sacituzumab govitecan)
Keytruda (pembrolizumab) or Keytruda Qlex	Triple-negative breast cancer that came back and can't be removed, or has spread	Treatment for advanced cancer	PD-L1 CPS of 10 or higher	Chemo

FDA labels on DailyMed: Keytruda, Keytruda Qlex. Tumor-agnostic approvals below can also apply.

Colorectal cancer

Brand (generic)	What it's approved for	When in treatment	Test result needed	Given with
Tecentriq (atezolizumab) or Tecentriq Hybreza	Stage III colon cancer	After surgery, to lower the chance of it coming back	dMMR (mismatch repair deficient)	A fluoropyrimidine (5-FU or capecitabine) and oxaliplatin
Jemperli (dostarlimab)	Stage II or III locally advanced rectal cancer	First treatment (approved October 2026 under accelerated approval)	MSI-H or dMMR	Given alone
Keytruda (pembrolizumab) or Keytruda Qlex	Colorectal cancer that can't be removed with surgery or has spread	Any line, including first treatment	MSI-H or dMMR	Given alone
Opdivo (nivolumab) plus Yervoy (ipilimumab)	Colorectal cancer that can't be removed with surgery or has spread (ages 12 and up)	Any line, including first treatment	MSI-H or dMMR	Each other
Opdivo (nivolumab) or Opdivo Qvantig	Colorectal cancer that has spread and grew after a fluoropyrimidine, oxaliplatin, and irinotecan (ages 12 and up)	Later treatment	MSI-H or dMMR	Given alone
Opdivo Qvantig (nivolumab and hyaluronidase)	Colorectal cancer that can't be removed or has spread (ages 12 and up, at least 30 kg)	Continued alone after IV Opdivo plus Yervoy	MSI-H or dMMR	Given alone

FDA labels on DailyMed: Tecentriq, Tecentriq Hybreza, Keytruda, Keytruda Qlex, Opdivo, Opdivo Qvantig, Yervoy and the FDA notice for Jemperli in rectal cancer. Tumor-agnostic approvals below can also apply.

Prostate cancer

Brand (generic)	What it's approved for	When in treatment	Test result needed	Given with
Provenge (sipuleucel-T)	Castration-resistant prostate cancer that has spread and causes no or only mild symptoms	Treatment for advanced cancer	None required	Given alone. Made from your own immune cells

FDA labels on DailyMed: Provenge. Tumor-agnostic approvals below can also apply.

Ovarian, fallopian tube, and primary peritoneal cancer

Brand (generic)	What it's approved for	When in treatment	Test result needed	Given with
Keytruda (pembrolizumab) or Keytruda Qlex	Platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer	After 1 or 2 earlier treatment regimens	PD-L1 CPS of 1 or higher	Paclitaxel, with or without bevacizumab (Avastin)

FDA labels on DailyMed: Keytruda, Keytruda Qlex. Tumor-agnostic approvals below can also apply.

Approvals for any solid tumor with certain test results

These apply to every cancer above, including prostate and ovarian cancer, when the tumor has the right test result.

Brand (generic)	What it's approved for	Test result needed
Keytruda (pembrolizumab) or Keytruda Qlex	Any solid tumor that can't be removed or has spread, and grew after earlier treatment, with no other good options	MSI-H or dMMR
Keytruda (pembrolizumab) or Keytruda Qlex	Any solid tumor that can't be removed or has spread, and grew after earlier treatment, with no other good options	TMB-H, defined since October 2026 as 13 or more mutations per megabase
Jemperli (dostarlimab)	Any solid tumor that has come back or is advanced, and grew after earlier treatment, with no other good options (adults)	dMMR

Sources: Keytruda label, Jemperli label, and the FDA notice updating the TMB-H cutoff. Keytruda Qlex shares these approvals for ages 12 and up.

Other cancers, such as melanoma and kidney cancer, have more approvals that aren't listed here. We check the FDA's list of new cancer approvals for changes.

Immune side effects, organ by organ

Here's what each one can feel like, in plain words. Your FDA drug label lists the full set for your exact drug.

🧴 Dermatitis (rash and itching)

Rash, itching, dry skin, or patches of lighter skin (vitiligo). This is one of the most common and earliest effects. Blisters, peeling, or sores in the mouth or eyes are an emergency.

More help: Dermatitis (skin rash and skin changes)

🚽 Colitis (bowel inflammation)

More bowel movements than usual, watery stools, belly pain or cramps, or blood or mucus in your stool. With immunotherapy, diarrhea should be reported the same day.

More help: Diarrhea (loose, watery stools)

🦋 Thyroiditis, hypophysitis, and adrenal insufficiency (hormone gland inflammation)

Feeling very tired, cold or hot, weight changes, a racing heart, headaches, dizziness, or vision changes. Some hormone problems are permanent and are managed with daily hormone pills.

🫁 Pneumonitis (lung inflammation)

A new or worsening cough, shortness of breath, or chest pain. Always report breathing changes right away.

🧪 Hepatitis (liver inflammation)

Yellow skin or eyes (jaundice), dark urine, pain on the right side of the belly, or bruising easily. It often shows up first on routine blood tests.

🩸 Type 1 diabetes (high blood sugar)

Rare, but it can come on fast: very thirsty, peeing a lot, fruity breath, nausea, or confusion. This needs care right away.

💧 Nephritis (kidney inflammation)

Peeing less, swelling in the legs or ankles, or blood in the urine. Your team checks kidney blood tests.

❤️ Myocarditis, neuropathy, myositis, arthritis, and uveitis (heart, nerve, muscle, joint, and eye inflammation)

Chest pain, a racing or skipping heartbeat, new weakness, numbness, muscle aches, joint pain or swelling, or eye pain, redness, or blurry vision. Heart and nerve problems are rare but serious.

What your care team may do

Check blood tests before each dose, including liver, kidney, thyroid, and blood sugar levels.
Grade the side effect from mild (grade 1) to severe (grade 4) to decide the next step.
For mild problems, keep going with extra checks and comfort care, such as creams for itching.
For moderate or severe problems, pause the drug and give steroids or other medicines that calm the immune system. They may refer you to a specialist, such as a gastroenterologist or endocrinologist.
Replace hormones, such as thyroid hormone, if a gland stops working.

Your team decides what fits you. We never list doses; follow your own care plan.

🏠 Things you and your family can do

Keep a simple daily log of bowel movements, energy, skin, and breathing, so changes stand out.
Carry your immunotherapy wallet card (or a photo of your drug list) and show it at every ER or urgent care visit.
Tell every doctor, dentist, and pharmacist that you've had immunotherapy, even after it ends.
Use gentle, fragrance-free soap and moisturizer, and protect your skin from the sun.
Ask before starting any new medicine, vitamin, or supplement.
Save your team's after-hours phone number in your phone and your loved ones' phones.

Call your care team now if you have:

Diarrhea, more bowel movements than usual, or blood or mucus in your stool
A new cough, shortness of breath, or chest pain
Yellow skin or eyes, dark urine, or pain on the right side of your belly
A rash with blisters, peeling, or sores in your mouth or eyes
Severe headache, dizziness, vision changes, or extreme tiredness
Being very thirsty, peeing a lot, or confusion
A fever of 100.4°F (38°C) or higher
Muscle weakness, numbness, or a racing or skipping heartbeat

Call 911 for trouble breathing, chest pain, confusion, or fainting.

💜 How loved ones can help

Gently ask each day how they're feeling, and help keep the symptom log.
Notice changes they might brush off, such as being more tired, coughing, or skipping meals.
Make the call with them if something new comes up. You can say, "They're on immunotherapy and have a new symptom."

Questions people often ask

When do immunotherapy side effects start?

Most show up in the first few months, but they can begin any time during treatment and even months after the last dose. That's why it helps to tell every doctor, nurse, and ER that you have had immunotherapy.

Are immunotherapy side effects the same as chemo side effects?

No. Checkpoint inhibitors don't usually cause hair loss or low blood counts the way chemo does. Instead, the boosted immune system can inflame healthy organs, such as the skin, bowel, thyroid, lungs, or liver.

Do side effects mean the treatment is working?

Not necessarily. Some studies have suggested a link, but many people do well with few or no side effects. Having no side effects doesn't mean the drug isn't working.

How are immune-related side effects treated?

It depends on the organ and how severe it is. Your team may pause the drug, give steroids or other medicines that calm the immune system, or replace hormones such as thyroid hormone. Many people can restart treatment later.

Should I take steroids or other medicines on my own?

No. Don't start, stop, or change any medicine without talking to your care team first, including over-the-counter pain relievers, supplements, and anti-diarrhea medicine.

Written by the Cancer Side Effects Guide team from FDA labels and leading cancer centers. Not medical advice. · Last updated: October 15, 2026 · How we write

Not medical advice. This page is general information to help you talk with your care team. It can't replace advice from your doctor or nurse. If you have a fever of 100.4°F (38°C) or higher during treatment, or any symptom that worries you, call your care team now. In an emergency, call 911.

Sources

Last updated: October 15, 2026. We summarize these sources in our own words.