CTLA4 and neoplasm: - 131I-Cat- and CpG-co-laden injectable hydrogel that causes oxygenation by Cat-triggered decomposition of endogenous H2O2, enhancing radioimmunotherapy efficacy with a low dose of radioactivity. Based on the “vaccine-like” function of hydrogels, distant metastatic cancers were effectively eliminated when combining treatment with anti-CTLA-4 antibody.- Less invasive and easy application compared to the implantable 125I beads.- Long-term relief of tumor hypoxia and effective primary tumor elimination under low doses of radiation.