Abstract: The use of immune checkpoint inhibitors (ICIs) for immunotherapy has launched a new era of tumor treatment. At present, ICIs are widely used in the treatment of patients with advanced metastatic colorectal cancer. Predictive markers are important tools for accurately screening patients that can benefit from ICIs. This paper reviews and summarizes the uses of predictive markers in the treatment of colorectal cancer with ICIs. For example, the paper includes discussions of markers for mismatch repair defects and microsatellite instability, tumor mutation burden, DNA polymerase ε/DNA polymerase δ1, and PD-L1 expression. Understanding the predictive value of these markers for treatment response and patient prognosis will help doctors to screen potential beneficiaries, improve treatment efficiency and provide more accurate treatment.