Programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) pathway blockade showed effective and durable antitumor effects in a wide range of tumors [3]; however, its therapeutic effect in CRC is not as potent as in other tumors, and only a minority of patients benefit from approved checkpoint inhibitors [4]. The gene discussed is PDCD1; the disease is colorectal carcinoma.