Jean Klastersky, MD, PhD of Institut Jules Bordet, Brussels, Belgium talks about the severity of side effects associated with immune checkpoint inhibitors. The side effects are relatively common, but they are rarely severe. However, Prof Klastersky points out that in some cases they may be life threatening, which requires fast detection and treatment. This is a difficult task for clinicians, as there are no biomarkers, which can predict the severity of complications. Corticosteroids are used to counteract the side effects, followed by more potent immunosuppressants. Depending on the situation the checkpoint inhibitor treatment may be discontinued. Combining two different classes of checkpoint inhibitors becomes a common practice, but this increases the incidence and severity of the side effects. Recorded at the Multinational Association of Supportive Care in Cancer (MASCC) and International Society of Ocular Oncology (ISOO) 2016 Annual Meeting on Supportive Care in Cancer held in Adelaide, Australia.