PDCD1 and colorectal carcinoma: Coincident data demonstrated that compared with those with proficient MMR (pMMR) tumors, dMMR CRC patients had better stage-adjusted clinical outcome [6,7] and might benefit differently from a variety of therapies including adjuvant chemotherapy (fluoropyrimidine, platinum compounds, topoisomerase inhibitors, and alkylating agents), targeted therapy (anti-epithelial growth factor receptor (EGFR) or anti-vascular endothelial growth factor (VEGF) antibodies) and immune checkpoint inhibitor therapy (anti-programmed cell death 1 (PD-1) antibodies) [2,3,8,9].