For a combination of immunotherapy and chemotherapy, pH/reduction dual-responsive co-delivery micelles were developed using chitosan-coated hyaluronic acid micelles that deliver DOX and programmed death-ligand 1 small interfering RNA (siPD-L1) together [131]. In vivo studies showed that the micelle exhibits a significantly stronger anti-breast cancer effect due to increased uptake of DOX mediated by CD44-hyaluronic acid interaction followed by increased generation of CD4 + /CD8 + T cells by silencing PD-L1 expression. The gene discussed is CD274; the disease is breast cancer.