Engineers at the University of Pennsylvania reported a lipid nanoparticle (LNP) platform that reinvigorates exhausted T cells in solid tumors by altering immune metabolism and delivering modulatory payloads; preclinical models showed restored T‑cell function and improved tumor control. In parallel, other groups described engineered LNPs that actively modulate immune cell metabolism to enhance vaccine and therapeutic responses. Both efforts reposition LNPs from passive delivery vehicles to immunometabolic modulators—designing lipid composition and payload to reshape local immune energetics. The approaches are built on mechanistic studies linking nanoparticle composition to myeloid and T‑cell programming and may inform next‑generation mRNA vaccines and immunotherapies that require both delivery and metabolic reshaping to overcome suppressive tumor microenvironments.