Secondly, the EH can self-assemble into nanofibers, the charged residues D, E, K and H in EH can stack into β-sheets through electrostatic interactions and endue the EH 'pH-responsive switch' .The introduction of nonpolar residues Y and F further can stabilize the supramolecular structure through hydrophobic interactions . Thirdly, the EH can co-assembly with the negatively charged Ag2S via electrostatic interactions (EH@Ag2S) at pH>6.0. The formation of the EH@Ag2S co-assembly plays a better role in encapsulating Ag2S, solving Ag2S inability to target and specifically recognize tumor cells. In addition, due to Ag2S small size, they usually identified as a foreign body by the reticuloendothelial system . The co-assembled system we constructed effectively avoids itself easy to be metabolic excreted during blood circulation and insufficient tumor accumulation . For in vivo, EH can programmatically recognize and block PD-L1, after entering the cell then release Ag2S owing to pH transformation changes the EH surface charge makes the electrostatic interaction between EH and Ag2S disappear. Ag2S can induce cell apoptosis through generating highly toxic ROS under the activation of US irradiation, which synergistically promotes the tumor immune microenvironment improvement. Overall, co-assembled system EH@Ag2S may serve as potential candidates for antibody-free immune checkpoint inhibition, and SDT provides an alternative strategy for amplifying ICB immunotherapy to achieve a remarkable superadditive (1 + 1 > 2) antitumor effect. Scheme 1. Schematic illustration of the carrier-free co-assembled system for PD-L1 blockade and sonodynamic therapy.