ZEB1 and non-small cell lung carcinoma: Because TGFβ signaling pathway is regulated by PD-L1 expression (Fig. 1a) and the TGFβ-Smad signaling pathway induces variable EMT transcription factors including the Snail family (Snail, Slug), ZEB family (ZEB1, ZEB2), and basic helix-loop-helix family (Twist and others) [41], we hypothesized that TGFβ might be involved in PD-L1-induced EMT of NSCLC.