CAT and neoplasm: M1 macrophage‐derived exosomes with catalase (CAT) and anti‐PD‐L1 (programmed death ligand‐1) nanobody expressed on membrane and DNA damage repair inhibitor (DDRi) encapsulated inside is engineered as effective radiotherapy sensitizers, realizing the trilogy of radiotherapy sensitization: the relief of tumor hypoxia, the inhibition of DNA damage repair, and the remodeling of tumor suppressive immune microenvironment.