Common ICIs include nivolumab and pembrolizumab (targeting programmed cell death protein-1 (PD-1)); atezolizumab, avelumab, and durvalumab (targeting programmed cell death protein ligand-1, (PD-L1)); and ipilimumab and tremelimumab (targeting cytotoxic T-lymphocyte–associated antigen 4, (CTLA-4)), revolutionizing cancer care over the past decade [246]. Here, PDCD1 is linked to cancer.