Scheme 1.

Schematic illustration of the PD-L1-targeting ROS-responsive micelle for combined immunotherapy and chemotherapy. (a) The anti-PD-L1 peptide modified amphiphilic block polymer pep-PAP self-assembled with PTX in water to form micelles (pep-PAPM@PTX). (b) pep-PAPM@PTX binded the cell surface PD-L1 multivalently and drove its recycling to lysosome degradation, thus downregulating PD-L1 expression. Meanwhile, pep-PAPM@PTX released PTX in response to elevated ROS levels, exerting cell-killing abilities to synergize immunotherapy.