Inducing immunogenic cell death (ICD) is a promising approach to elicit enduring antitumor immune responses. Hence, extensive efforts are being made to develop ICD inducers. Herein, a cascaded dual-atom nanozyme with Fe and Cu sites (FeCu-DA) as an efficient ICD inducer is presented. The Fe and Cu dual-atom sites synergistically enhance peroxidase (POD) and catalase activities, effectively converting intratumoral hydrogen peroxide (H