Exosomal PD-L1 contributes to immunosuppression and is associated with anti-PD-1 response

Tumor cells evade immune surveillance by upregulating the surface expression of programmed death-ligand 1 (PD-L1), which interacts with programmed death-1 (PD-1) receptor on T cells to elicit the immune checkpoint response. Anti-PD-1 antibodies have shown remarkable promise in treating tumors, including lung cancer and metastatic melanoma. However, there is a problem that PD-1/PD-L1 blockade is associated with a response rate is low. A better understanding of PD-L1-mediated immune evasion is needed to predict patient response and improve treatment efficacy.