Engineered outer membrane vesicles are being explored as a way to enhance CAR-T cell therapy for solid tumors. Research in this area involves various approaches, including the use of biomimetic vesicles, exo-nanomaterials, and bacteria, to modulate the tumor immune microenvironment. The development of these therapies is an active area of study, with potential applications in cancer immunotherapy, including treatment of skin melanoma and other solid tumors.