The relief of tumor hypoxia was further examined by analyzing the expression level of the transcriptional regulator hypoxia‐inducible factor 1α (HIF‐1α), which is the key mediator of physiological and pathophysiological responses to hypoxia.[42] LLC tumor‐bearing mice were divided into six groups with different treatments: (1) PBS + Irradiation (IR); (2) DDRi@PD‐M1Exos + IR; (3) DDRi@CAT‐PD‐M1Exos + IR; (4) PBS; (5) DDRi@PD‐M1Exos; (6) DDRi@CAT‐PD‐M1Exos. This evidence concerns the gene HIF1A and neoplasm.