STING1 and neoplasm: Herein, we constructed a multifunctional nanoplatform (termed MD1a NP) designed to elicit personalized antitumor immunity and overcome tumor immunosuppression by co-assembling a hypochlorous acid (HOCl)-responsive methylene blue (MB)–doxorubicin (DOX) dimer prodrug with a stimulator of interferon genes (STING) agonist (1a).