CTLA4 and melanoma: Although there are various predictive factors for the efficacy of immune checkpoint inhibitors in clinical practice, such as neutrophil-to-lymphocyte ratio, lactate dehydrogenase, and liver metastasis6,17–20, limited data from patients with melanoma treated with PD-1 or cytotoxic T-lymphocyte–associated protein (CTLA)-4 inhibitors indicate that skeletal muscle loss is associated with worse overall survival and higher frequency of toxicity21,22.