Abstract: Regulatory T cells （Tregs） are key regulators of the immune system and play important roles intumorigenesis and tumor progression. They exert immunosuppressive effects through immune checkpoint pathways and by secreting inhibitory cytokines and specific chemokines as well as through other mechanisms that promote tumor immune escape. However, their mechanisms of action are complex and involve multistage, multifactorial processes. This article summarizes the mechanisms by which Tregs exert immunosuppressive effects in tumors and promote immune escape and describes related research progress. This study aims to provide a reference for an indepth understanding of immune regulatory mechanisms in tumors and the development of novel therapeutic strategies.