PDCD1 and melanoma: Typical ICIs include monoclonal antibodies against PD-1, PD-L1, and CTLA-4, which have been approved for clinical use in treating various solid tumors such as melanoma [3, 27, 28], NSCLC [2, 29–31], RCC [5, 13, 30, 32], and TNBC [4, 33–35].