The immune checkpoint inhibitors (ICI) have radically changed the treatment and the prognostic of certain types of cancer. This reprogramming of the immune system can sometimes lead to immuno-related adverse events (irAEs) involving, depending on the immunotherapy used, multiple organ (s) with different severity, frequency and chronology. In theory all organs can be affected, often in a reversible and rapid manner if an immunosuppressive therapy is initiated in time. In contrast, endocrinopathies and some neuropathies are of long lasting and sometimes of irreversible nature. The management of high-grade autoimmune toxicities requires, first, the suspension of treatment and second, the introduction of steroids as first-line or, in case of failure, of a second immunosuppressive agent.