In CRC, immune checkpoint inhibitors (ICIs) primarily act by blocking the interaction between programmed cell death protein 1 (PD-1) and its ligand PD-L1, and also by inhibiting the function of cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) (Jiao et al., 2020). This evidence concerns the gene PDCD1 and colorectal carcinoma.