A study in Nature Biomedical Engineering reported that engineered outer membrane vesicles (OMVs) can boost CAR‑T cell activity against solid tumors. Researchers modified bacterial OMVs to deliver immune-stimulatory signals and tumor-targeting cues, enhancing CAR‑T infiltration, persistence, and anti-tumor potency in preclinical solid-tumor models. The approach addresses persistent barriers to CAR‑T efficacy in solid cancers—immune suppression and poor tumor penetration—and suggests a modular adjunct that could be combined with cell therapies to broaden indications beyond hematologic malignancies. The team reported improved tumor control and survival in treated animals, positioning OMVs as a potential translational adjunct to CAR‑T programs.