HAVCR2 and colorectal carcinoma: 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.