STAT3 and breast cancer: As previous study has reported that blocking of STAT3 in breast cancer cells induced an antitumor immune response involving CD4+ T cells (Fig. 3a), which may ameliorate TME via secretion of cytokines, such as TNF-α, IFN-γ, IL-6, and IL-5, as well as chemokines CCL5 and CXCL10 [125].