CAT and cancer: The simultaneous release of NO and O2 from CCM-CeO2 was triggered by excessive H2O2 in the tumor microenvironment, which sensitizedTMZ chemotherapy by inducing intracellular ROS, damaging lysosomalmembrane integrity, and further triggering apoptosis and necrosis.This study elucidated that chemotherapy enhanced by our synthesizednanoceria was more likely to be attributed to its catalase-like activity.Overall, this work provides a facile targeting and hypoxia-alleviatingstrategy to potentiate chemotherapy for cancer therapy.