ICIs, particularly those targeting PD-1/PD-L1 (programmed Death protein 1/programmed Death-Ligand 1) pathway and CTLA-4 (cytotoxic T-lymphocyte associated protein 4), have changed cancer treatment paradigm, offering significant clinical benefits in various cancer types, including melanoma, non-small cell lung cancer (NSCLC), kidney cancer and many others (2). The gene discussed is PDCD1; the disease is melanoma.