CAT and cancer: For instance, a bovine serum albumin‐iridium oxide nanoparticle (BSA‐IrO2 NPs) has been reported, which not only showed outstanding photothermal conversion efficiency and high X‐ray absorption capability but also had CAT‐mimicking activity.[58] Further, it is demonstrated that IrOx nanozyme displays multienzyme‐mimetic activities, including POD‐ and OXD‐mimicking and pH‐dependent CAT‐mimicking activities for antitumor.[59] Another work synthesized a generation 5 dendrimer/gold (G5Au) NPs that, with intrinsic CAT‐like properties, can decompose H2O2 for relieving cancer hypoxia.[60]