Furthermore, natural catalase (CAT) and nanozymes with CAT-like properties can also overcome the hypoxic TME through the in situ catalytic decomposition of tumour-overexpressed hydrogen peroxide (H2O2) and the in situ generation of O2 (Liang et al., 2017; Ai et al., 2018; Liang et al., 2018; Chang et al., 2019; Liu et al., 2019; Yu et al., 2019). Here, CAT is linked to neoplasm.