ICIs targeting CTLA4 (ipilimumab), PD-1 (nivolumab, pembrolizumab, cemiplimab), and the PD-1 ligand programmed death-ligand 1 (PD-L1; atezolizumab, avelumab, durvalumab) are approved for the treatment of various solid tumors, including melanoma, non-small-cell lung cancer, and urothelial carcinoma3,4. Here, PDCD1 is linked to melanoma.