Fig. 3

Strategies being exploited to overcome challenges in CAR-T therapy in solid tumor. Various strategies are currently being tested in preclinical and clinical studies to overcome the challenges facing CAR-T therapy for solid tumor (gray), including a, b enhancing T cell (beige) trafficking, c reforming tumor microenvironment (pink represented physiological barriers), d, e anti-immunosuppression, elevating antigen recognition towards tumor (f, g), and healthy cells (darker beige) (h), as well as i–l improving safety control using suicide switch or on-switch. Detailed mechanisms were further illustrated in the section “Overcoming Challenges with Smarter CAR Designs”