Immunotherapy often incurs side-effects, mainly involving the skin, digestive tract and endocrine system. The most frequent endocrine side-effects involve the pituitary and thyroid glands. Cases of insulin-dependent diabetes, whether autoimmune or not (type 1 or 1B) have been reported with PD-1/PD-L1 inhibitors, alone or in association with anti-CTLA-4 antibodies, and were systematically associated with sudden-onset insulinopenia, frequently leading to ketoacidosis or fulminant diabetes, requiring first-line insulin therapy. This adverse effect has not so far been reported with anti-CTLA-4 monotherapy.