CD8A and melanoma: In another study, doxorubicin (DOX), all‐trans retinoic acid (ATRA), and IL‐2 were codelivered in the biodegradable hollow mesoporous silica nanoparticle (MSNP) to treat B16F10 melanoma.156 ATRA induces differentiation of MDSCs into matured DCs and macrophages, and IL‐2 stimulates the proliferation and activation of CD8+ T cells.229 In this combinational treatment strategy, a reduced dosage of DOX (2.5 mg kg−1, lower than conventional injection dose of 5 mg kg−1) was able to generate adequate immunogenic tumor peptide antigens, so the systemic toxicity was minimized.