Currently, after the research results of PD-1 inhibitors and CTLA-4 inhibitors in the treatment of CRC, novel immune checkpoints such as TIM-3, TIGIT, and LAG-3 are not only potential biomarkers for diagnosis, prognosis, and survival prediction of CRC patients but also the next breakthrough point in immunotherapy for CRC. Here, PDCD1 is linked to colorectal carcinoma.