ABSTRACT
Colorectal cancer is the third most common cancer in the world. The treatments include surgery, chemotherapy, radiotherapy and targeted therapy. The guidelines of many tumor types have been rewritten with the advent of immune checkpoint inhibitors. There are significant differences in the efficacy of immune checkpoint inhibitors in colorectal cancer according to microsatellite status. Microsatellite instability-high (MSI-H) colorectal cancer has made a breakthrough in immunotherapy, whether in the late-line, first-line, adjuvant or neoadjuvant therapy. The success of KEYNOTE-177 study has changed the guidelines with pembrolizumab becoming a standard treatment in the first-line treatment of MSI-H advanced colorectal cancer. The NICHE study, which used immunotherapy as neoadjuvant treatment of colorectal cancer, has made exciting achievements in MSI-H colorectal cancer. For microsatellite stability (MSS) colorectal cancer, many studies are ongoing, and immunotherapy is still unable to challenge the status of traditional treatment. In this paper, we review the clinical trials related to immune checkpoint inhibitors of colorectal cancer, expecting to provide references for the development of colorectal cancer immunotherapy.