Two independent preclinical programs reported that nanoparticle platforms can concentrate IL‑12 in ovarian tumors and boost responses to checkpoint blockade. MIT and collaborators described polymer‑coated nanoparticles that localize IL‑12 in the tumor microenvironment, enabling strong antitumor immunity and memory in mouse models of metastatic ovarian cancer (Nature Materials). A separate MIT‑linked team engineered surface‑display nanoparticle designs that anchor cytokine to tumor cells, promoting localized immune activation while limiting systemic cytokine exposure. Both groups showed high response rates in preclinical metastasis models and durable immune memory on rechallenge. The work underscores cytokine delivery as a strategy to overcome immunosuppressive tumor niches; companies developing targeted cytokine platforms or combination regimens with PD‑1/PD‑L1 inhibitors may view these data as enabling translational programs, provided safety and delivery scale can be managed.