Immunotherapy is an essential component of cancer care and expands the treatment possibilities for patients. Immune checkpoint inhibitors are among the most promising drugs but are associated with toxicities. The most frequently occurring ones affect skin, colon, endocrine organs, liver and lungs. Others are very infrequent but may be very serious, even lethal, such as neurological disorders and myocarditis. These new ESMO Clinical Practice Guidelines provide an overview of the main immune-related adverse events and include recommendations for their management.