IDO1 and neoplasm: With co-loading of chemotherapeutic agent DOX as the ICD inducer and aNLG919 as an IDO1 inhibitor, DNCaNPs after i.v. injection could induce effective immunogenic tumor cell death, thus promoting DCs maturation, CD3+CD8+ T lymphocyte infiltration, and cytotoxic IFN-γ secretion, as well as in meanwhile significantly restricting intratumoral frequency of immunosuppressive Tregs.