Artificial Enzyme‐Catalyzed Cascade Reactions for Antitumor Immunotherapy Reinforced by NIR‐II Light

: Current cancer therapy is seriously challenged by tumor metastasis and recurrence. One promising solution to these problems is to build antitumor immunity. However, immunotherapeutic efficacy is highly impeded by the immunosuppressive state of the tumors. Here a new strategy is presented, catalytic immunotherapy based on artificial enzymes. Cu2-x Te nanoparticles exhibit tunable enzyme-mimicking activity (including glutathione oxidase and peroxidase) under near-infrared-II (NIR-II) light. The cascade reactions catalyzed by the Cu2-x Te artificial enzyme gradually elevates intratumor oxidative stress to induce immunogenic cell death. Meanwhile, the continuously generated oxidative stress by the Cu2-x Te artificial enzyme reverses the immunosuppressive tumor microenvironment, and boosts antitumor immune responses to eradicate both primary and distant metastatic tumors. Moreover, immunological memory effect is successfully acquired after treatment with the Cu2-x Te artificial enzyme to suppress tumor relapse.