Abstract: Myeloid-derived suppressor cells (MDSCs) are a heterogeneous group of cells that play a critical role in tumor-associated immune suppression. MDSCs allow tumors to evade immune surveillance through immunosuppressive effects. The infiltration of MDSCs into cancer tissues is associated with poor prognosis and resistance to therapies. MDSCs play an important role in metastasis, but the mechanism by which MDSCs establish the pre-metastatic microenvironment in distant organs is largely unknown. This article reviews the role of MDSCs in cancer development and progression and the related mechanisms through which MDSCs participate in the formation of the pre-metastatic niche. The potential therapeutic value of MDSCs in tumor development and progression was also investigated.