PDCD1LG2 and neoplasm: On the one hand, TAMs produce inflammatory cytokines like IL-17 and IL-23, which increase genetic instability and on the other hand they can impede tumor immunosurveillance, and thus T cell-mediated antitumor immunity, by secreting immunosuppressive cytokines like TGF-β and IL-10, by expressing immune checkpoint ligands such as PD-L1, PD-L2, B7-H4, or VISTA (4, 187) or by producing reactive oxygen species (ROS).