FAS and neoplasm: This immune activation may be enhanced by systemic immunotherapy.40 Anti-PD-L1 antibodies alone are poorly cytotoxic; however, when combined with RT, they upregulate tumor cell MHC and FAS expression and enhance sensitivity to T cell cytotoxicity.33 Furthermore, RT enhances PD-L1 expression in tumors with inflammation,41 and distant tumors shrink following combination treatment with RT and PD-L1 antibody.42 Similarly, NIR-PIT can also enhance antitumor effects with ICIs.