Mount Sinai researchers reported an in vivo CAR‑T approach that selectively targets fibroblast activation protein alpha (FAP)‑expressing stellate cells and reduced liver fibrosis in models of metabolic dysfunction‑associated steatohepatitis (MASH). The therapy generates CAR‑T cells in vivo rather than ex vivo manufacturing, simplifying delivery and expanding potential scalability. The strategy not only reduced fibrosis but also reversed liver damage metrics in preclinical studies, indicating therapeutic activity beyond halting progression. The team emphasized specificity to stellate cells to avoid broad immunotoxicity. If translatable to humans, in vivo CAR‑T approaches could overcome manufacturing and cost barriers for cellular antifibrotic therapies—liver fibrosis is a leading unmet need with few disease‑modifying drugs.