免疫检查点抑制剂，如抗程序性细胞死亡-1、程序性细胞死亡配体-1和细胞毒性T淋巴细胞抗原-4单克隆抗体，在各种癌症中表现出明显的疗效。错配修复缺陷和微卫星不稳定性高的肿瘤已被确认为应答免疫检查点抑制剂的显著生物标志物。这些生物标志物显示出更高的突变负荷，具有与癌症相关的新抗原和稠密的免疫细胞浸润，从而产生强大的免疫反应。对于转移性结直肠癌，对于化疗难治的患者，推荐使用pembrolizumab和nivolumab联合ipilimumab治疗，对于化疗未经治疗的错配修复缺陷和微卫星不稳定性高的患者，推荐使用pembrolizumab。相反，错配修复正常和微卫星稳定的转移性结直肠癌患者在免疫检查点抑制剂单药治疗中没有临床益处。目前，已经研究了抗程序性细胞死亡-1/程序性细胞死亡配体-1和细胞毒性T淋巴细胞抗原-4单克隆抗体的联合治疗，以及免疫检查点抑制剂与分子靶向药物或放疗的联合治疗，以调节免疫细胞并增强错配修复正常和微卫星稳定的转移性结直肠癌的治疗效果。此外，免疫检查点抑制剂已被开发用于新辅助治疗和辅助治疗。在本综述中，我们总结了现有的临床数据，并讨论了关于结直肠癌的免疫检查点抑制剂治疗的未来展望。© 2023. 作者(们)独家许可给日本临床肿瘤学会。

Immune checkpoint inhibitors, such as anti-programmed cell death-1, programmed cell death ligand-1, and cytotoxic T-lymphocyte antigen-4 monoclonal antibodies, have been notably effective in various types of cancers. Mismatch repair deficiency and microsatellite instability-high tumors have been established as striking biomarkers for response to immune checkpoint inhibitors. These biomarkers show a higher mutational burden, have cancer-associated neoantigens, and dense immune cell infiltration, which generates a robust immune response. For metastatic colorectal cancer, pembrolizumab and nivolumab, with or without ipilimumab, are recommended for chemotherapy-refractory patients, and pembrolizumab is recommended for chemotherapy-naive patients with mismatch repair deficiency and microsatellite instability-high tumors. Conversely, patients with mismatch repair-proficient and microsatellite-stable metastatic colorectal cancer showed no clinical benefit from immune checkpoint inhibitor monotherapy. Currently, combination therapy with anti-programmed cell death-1/programmed cell death ligand-1 and cytotoxic T-lymphocyte antigen-4 monoclonal antibodies or a combination of immune checkpoint inhibitors with molecular targeting agents or radiotherapy have been investigated to modulate immune cells and enhance therapeutic efficacy in mismatch repair-proficient and microsatellite-stable metastatic colorectal cancer. Furthermore, immune checkpoint inhibitors have been developed for neoadjuvant and adjuvant settings. In this review, we summarize the existing clinical data and discuss future perspectives with a focus on immune checkpoint inhibitor-based treatments for colorectal cancer.© 2023. The Author(s) under exclusive licence to Japan Society of Clinical Oncology.