The programmed cell death protein 1 (PD1) antibodies pembrolizumab and nivolumab and the combination of nivolumab and ipilimumab (a cytotoxic T-lymphocyte associated protein 4 (CTLA4) antibody) have elicited effective and durable responses, and their use for treating CRC has been approved by the US Food and Drug Administration (FDA) (22). This evidence concerns the gene PDCD1 and colorectal carcinoma.