CTLA4 and melanoma: ,4 The survival rates of patients with irresectable stage III and metastatic stage IV melanoma have significantly improved since the introduction of systemic therapy with immune checkpoint inhibitors (ICIs) and targeted therapy (TT).5, 6, 7, 8 To enhance antitumor T-cell-mediated immune responses, ICIs block programmed cell death protein 1 (PD-1) (nivolumab or pembrolizumab) or cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) (ipilimumab).