Researchers at UCSF reported a dual‑vector platform that programs CAR‑T cells in vivo through cell‑specific delivery and site‑specific DNA integration, demonstrating stable CAR expression and therapeutic benefit in humanized mouse models. The team described programmable, locus‑specific insertion of large DNA payloads into T cells without ex vivo manufacturing—marking what investigators called the first demonstration of precise in‑body CAR‑T engineering with persistent effect. Independently, Azalea Therapeutics (a Jennifer Doudna lab spinout) published Nature results showing in vivo CAR‑T generation cleared both solid and blood tumors in mice by reliably editing the intended cells and genomic loci. Both reports emphasize improvements in safety vectors and targeting specificity, and they signal a possible shift away from centralized ex‑vivo CAR‑T manufacturing toward decentralized, in‑patient gene‑editing approaches. Translational hurdles remain—vector safety, off‑target risk, and human dosing—but the demonstrations establish a technical precedent for in vivo programmed cell therapy.