TGFB1 and cancer: Finally, the immunosuppressiveTME (immune cells and cytokines) unique to PC, changes in T cells (insufficient production, poor effect, impaired memory), and various classical cancer signaling pathways (TGFβ, WNT-β, CDK4/6, MAPK, PTEN) may be involved in the resistance of PD-1/PD-L1 inhibitors.