Treg cell polarization refers to the process by which naïve regulatory T cells differentiate into specific Treg subsets, such as iTreg and pTreg, under the influence of various cytokines and microenvironmental signals. These subsets differ in their transcription factors and surface markers, as well as in the targets and intensity of their immunosuppressive functions. This process serves as a key mechanism for regulating immune homeostasis and maintaining immune tolerance.