The phase II KEYNOTE-016 trial, which evaluated the efficacy of pembrolizumab as third-line or later treatment in MSI-H/dMMR CRC, MSI-H/dMMR non-colorectal solid tumors, and MSS CRC, reported response rates of 40%, 71%, and 0%, respectively [365], demonstrating the efficacy of anti-programmed cell death protein 1 antibodies in MSI-H/dMMR solid tumors. This evidence concerns the gene PDCD1 and colorectal carcinoma.