PDCD1LG2 and neoplasm: Furthermore, CAFs secrete FASL, which initiates apoptosis in CD8+ T cells that express FAS.511 The presence of TGF-β is recognized to hinder the anti-tumor immune responses by impeding the infiltration of CD8+ T cells into the tumor microenvironment.70 Moreover, the essential role of CXCL12 produced by CAFs is to disrupt the communication between CD8+ T cells and tumor cells, thereby reducing the efficacy of ICB therapy.513 CAFs regulate T cell functionality by modulating the levels of immune checkpoint proteins like PD-L1, PD-L2, B7-H3, and B7-H4.