Immunotherapy, including immune checkpoint inhibitors (ICIs) such as programmed cell death protein-l/programmed death-ligand 1 (anti-PD-1/PD-L1), has emerged as a promising and relatively safe therapeutic option for different types of cancers, including CRC, melanoma, and non-small cell lung cancer [9]. The gene discussed is PDCD1; the disease is colorectal carcinoma.