CD69 and neoplasm: CD69 not only functioned as an activation marker showing that CD8+PD-1+ T lymphocytes still exhibited cytotoxic activity after DOX@3D-MPs treatment, recent works have shown that CD69 behaved as a potential factor predicting the response to PD-1/PD-L1 blockade therapy,35,36 which prompted us to treat tumor with DOX@3D-MPs in combination with anti-PD-1 antibody (denoted as DOX@3D-MPs+anti-PD-1) to further improve the anticancer effects.