PDCD1 and colorectal carcinoma: Based on the KEYNOTE-177 and CheckMate 142 clinical trials, the anti-PD-1 molecules pembrolizumab and nivolumab, and the combination of nivolumab and the anti-CTLA-4 molecule ipilimumab have been approved by the Food and Drug Administration (FDA) for CRC treatment (Overman et al., 2017; Diaz et al., 2022; Lenz et al., 2022).