It has been reported that the Ir‐N5 SA can activate natural oxidase, peroxidase, and catalase, as well as catalyzing NAHD to H2O2.[12] However, it is challenging to promote the production of ∙OH by intracellular SOD and POD, thus, constant production of ∙OH inside cancer cells has been attempted by various approaches to enhance the cytotoxicity of ROS for anti‐tumor treatment.[13] Nanozymes could be developed to continuously convert endogenous ROS (O2∙− and H2O2) into ∙OH inside cancer cells. Here, CAT is linked to cancer.