Research Progress of Immune Checkpoint Inhibitors in Colorectal Cancer

Tumor immunity is a new line of research for the treatment of patients with solid tumors, and negative regulators of the immune system called immune checkpoints play a key role in limiting antitumor immunologic responses. Immune checkpoint inhibitors, such as those targeted against PD-1, PD-L1 and CTLA-4, have been developed as anti-tumor drugs. dMMR/MSI-H colorectal cancer is susceptible to immune checkpoint inhibitors with objective responses. Based on the immunophenotyping of colorectal cancer, this article reviews the treatment regimens of immune checkpoint inhibitors in colorectal cancer.