PDCD1LG2 and cancer: They are implicated in angiogenesis (VEGF, TGF-β, MMPs secretion), in migration and invasion (MMPs, EGF, serine proteases secretion), in epithelial to mesenchymal transition (EMT) (TGF-β secretion), in intravasation and extravasation (CCL18 chemokine production), in the interaction with cancer stem cells and finally they are implicated in immunosuppression (PD-L1/PD-L2 expression, IL-10, TGF-β, arginase-1 and prostaglandins production) [57].