CD274 and neoplasm: Specifically, after siRNA@PPDS being taken up by the cell, since the micelles could be disintegrated at ∼ pH 5.3 in the lysosome, the siRNA was released into the cytoplasm to reverse the exhaustion of T cells by silencing the PD-L1 protein of tumor cells to activate the killing function of the immune system against tumors; simultaneously, SAHA was also released due to the lipase catalyzing ester bond breaking between the PPD and SAHA to stimulate antitumor immunity of both tumor cells and host immune cells.