MIT and collaborators reported in Nature Materials that polymer‑coated nanoparticles engineered to deliver IL‑12 directly to ovarian tumor sites produced durable antitumor immunity when combined with immune checkpoint inhibitors. In mouse models the combination eradicated metastatic lesions in over 80% of animals and generated immune memory that protected against rechallenge. Senior authors Paula Hammond and Darrell Irvine described a ‘target‑and‑release’ design that concentrates cytokine in the tumor microenvironment to boost T‑cell responses while limiting systemic toxicity. The study highlighted surface‑borne IL‑12 presentation on cancer cells to prime immune attack. The preclinical results position targeted cytokine delivery as a strategy to sensitize immunotherapy‑resistant solid tumors and inform next steps for translating localized cytokine platforms into clinical studies.