Abstract: Although the overall survival rate of colorectal cancer has been significantly improved over the last decade, advanced colorectal cancer remains one of the main causes of death from malignant tumors globally. Chemotherapeutic drugs and biological agents are the main therapeutic methods for colorectal cancer. The recent success in the discovery of programmed cell death protein1 (PD-1) inhibitors in metastatic colorectal cancer patients with mismatch repair deficiency has generated overwhelming enthusiasm for its use in immunotherapy against the disease. In recent years, the efficacy of PD-1 inhibitors in colorectal cancer has become a hot topic. This review presents our current understanding of the immunophenotype and molecular changes in colorectal cancer and a novel combination therapy using inhibitors of the immune check-point.