Immune checkpoint blockade (ICB) using monoclonal antibodies (mAbs) specific to cytotoxic T lymphocyte antigen 4 (CTLA-4) and to programmed cell death 1 (PD-1) or its ligands has emerged as one of the most promising approaches in cancer immunotherapy to invigorate antitumor immunity (1, 2). This evidence concerns the gene PDCD1 and cancer.