TGFB1 and neoplasm: In addition, although it played an important role in the entry of CD8+ T cells into the TME, they gave an explanation for the incomprehensible result that CXCR3 expression was downregulated in the TME: it may be attributed to cell-extrinsic variables in the TME, such as inhibitory receptor signal transduction and TGF-β secreted by tumor cells (99).