While immunotherapy has revolutionized cancer treatment by harnessing the body's own immune system to target malignancies, it can also cause significant adverse effects known as immune-related adverse events. Because enhanced immune cells can lose self-tolerance, they may mistakenly attack healthy organs and tissues, leading to inflammation in the lungs, colon, liver, skin, and endocrine glands. Side effects range from mild fatigue and skin rashes to severe, life-threatening autoimmune conditions that require prompt immunosuppressive management.