Abstract: Immune checkpoint inhibitors (ICI) show surprising clinical responses in various malignancies, including colorectal cancer. However, considerable number of cancer patients displayed an unsatisfactory objective response rate (ORR) to the immune checkpoint inhibitors. Treatment resistance is a common feature and hyperprogression was noticed in some patients. It is important to discover biomarkers which can predict the efficacy of immunotherapy and help in screening the suitable patients. Biomarkers have shown value in predicting the efficacy of immune checkpoint inhibitors in colorectal cancer treatment, however, the optimal biomarkers still remain undiscovered. Large-scale prospective studies are required to confirm the value of the potential biomarkers in future. This article reviews the reported predictive biomarkers with positive and negative response to immune checkpoint inhibitors in colorectal cancer.