Immune-checkpoint blockade (ICB) demonstrated inspiring effect and great promise in anti-cancer therapy. However, many obstacles, such as drug resistance and difficulty in patient selection, limited the efficacy of ICB therapy and awaited to be overcome. By timely identification and intervention of the key immune-suppressive promotors in the tumor microenvironment (TME), we may better understand the mechanisms of cancer immune-escape and use novel strategies to enhance the therapeutic effect of ICB. Myeloid-derived suppressor cell (MDSC) is recognized as a major immune suppressor in the TME. In this review, we summarized the roles MDSC played in the cancer context, focusing on its negative biologic functions in ICB therapy, discussed the strategies targeted on MDSC to optimize the diagnosis and therapy process of ICB and improve the efficacy of ICB therapy against malignancies.

免疫检查点阻断 (ICB) 在抗癌治疗中表现出鼓舞人心的效果和巨大的前景。然而，许多障碍，如耐药性和患者选择困难，限制了ICB治疗的疗效，有待克服。通过及时识别和干预肿瘤微环境（TME）中关键的免疫抑制启动子，我们可以更好地了解癌症免疫逃逸的机制，并采用新的策略来增强ICB的治疗效果。髓源性抑制细胞 (MDSC) 被认为是 TME 中的主要免疫抑制因子。在这篇综述中，我们总结了 MDSC 在癌症背景下的作用，重点关注其在 ICB 治疗中的负面生物学功能，