TGFB1 and cancer: Though Tregs do not need to produce their own TGF-β1 to repress the effector T-cell functions in the TME12, this study reveals that Tregs, and particularly the Itgβ8pos population, are essential to increase the levels of activated TGF-β produced by cancer cells responsible for efficient repression of T-cell cytotoxic functions within the TME.