STAT3 and neoplasm: STAT3 and its active form, pSTAT3, are intracellular signaling molecules that act only within cells, whereas TGFβ can transmit signals within and between cells (22); accordingly, TGFβ plays an important role in coordinating the joint actions of the tumor ecosystem—for example, bispecific antibodies that target both TGFβ and PD-L1 can overcome TGFβ-mediated immunotherapy resistance (41).