CAT and neoplasm: Another strategy to improve the O2 content in a tumor is in situ catalytic decomposition of endogenous H2O2 to produce O2, including CAT[16] and Nanozymes with CAT‐like activity.[17] However, these methods are limited by the low endogenous H2O2 levels, low catalytic efficiency, and potential metal catalyst toxicity.[16, 18] An alternative strategy has been proposed, using biomimetic photosynthesis to generate oxygen.[19] Compared to the first two oxygen supply methods, algae has distinct advantages, including high biocompatibility and continuous oxygen production.[20, 21]