结直肠癌（colorectal cancer，CRC）是我国乃至全世界常见的恶性肿瘤，转移事件发生率高。免疫治疗在转移性结直肠癌（metastatic CRC，mCRC）的治疗中作为一种新兴的治疗方法，受到的关注越来越多。免疫检查点抑制剂（immune checkpoint inhibitor，ICI）是其中一种重要手段，主要以程序性死亡受体1（programmed death-1，PD-1）、程序性死亡受体配体1（programmed death-ligand 1，PD-L1）和细胞毒性T淋巴细胞相关抗原4（cytotoxic T lymphocyte-associated antigen 4，CTLA-4）抗体为代表。已经完成的和正在进行中的相关临床试验均肯定了ICI在mCRC治疗中的巨大潜力。美国食品药品监督管理局已经批准多个ICI用于微卫星高不稳定性（microsatellite instability-high，MSI-H）/错配修复缺陷（mismatch repair deficient，dMMR）的mCRC的一线治疗。尽管ICI在微卫星稳定（microsatellite stable，MSS）/错配修复正常（mismatch repair proficient，pMMR）的mCRC的治疗中尚不能撼动传统治疗的地位，但越来越多的ICI联合方案相继进入临床试验阶段，初步显示了良好的临床疗效和应用前景。寻找新的标志物用以甄别可能获益的患者群体和试验验证新的联合方案疗效，以及开发新的免疫检查点都将是ICI未来研究的重要方向。

Colorectal cancer (CRC) is a common malignancy with a high incidence of metastatic events in China and the world. Immunotherapy has received increasing attention as an emerging therapy in the treatment of metastatic colorectal cancer (mCRC). Immune checkpoint inhibitor (ICI) is one of the important methods, mainly represented by programmed cell death protein 1 (PD-1), programmed cell death ligand 1 (PD-L1) and cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) antibodies. The strong potential of ICIs in the treatment of mCRC has been confirmed by completed and ongoing clinical trials. The U.S. Food and Drug Administration has approved some ICIs for the first-line treatment of microsatellite instability-high (MSI-H)/mismatch repair deficient (dMMR) mCRC. ICI cannot yet replace the conventional therapy in the treatment of microsatellite stable (MSS)/mismatch repair proficient (pMMR) mCRC, but an increasing number of ICI combination programs have entered the clinical trial phase and have initially shown good clinical efficacy and application prospects. Finding new markers to identify potentially beneficial patients, validating new combination regimens, and developing new immune checkpoints are all important to the future of ICI research.