A three-dimensional scaffold inspired by the physiological process of T-cell proliferation in lymph nodes was developed to enhance the therapeutic effects of chimeric antigen receptor (CAR)-T cells against solid tumors. This scaffold, made from poly(lactic-co-glycolic acid) (PLGA) via microfluidic technique, provides a porous structure with bio-functional stimulatory signals, including anti-CD3, anti-CD28 antibodies, and cytokines, to support the loading, delivery, activation, and expansion of CAR-T cells. The scaffold enables a 50-fold expansion of CAR-T cells in vitro and a 15-fold expansion in vivo. It maintains long-lasting expansion of CAR-T cells for up to 30 days in a cervical tumor model and significantly inhibits tumor growth. The scaffold was modified with T-cell stimulatory signals to mimic the environment of lymph nodes, promoting CAR-T cell proliferation and activity. In vivo studies showed that the scaffold supports sustained CAR-T cell activation and expansion within tumors for up to 30 days. The scaffold was also effective in delaying tumor progression in a xenograft tumor model. The scaffold serves as a CAR-T cell expansion niche in vivo, enhancing CAR-T cell expansion and prolonging their efficacy. The scaffold was found to be safe and could be injected into patients along with prepared CAR-T cells without separation. The scaffold can also be used as a delivery system to load and reserve CAR-T cells. The study demonstrated the therapeutic success in subcutaneous tumors, but further research is needed to apply the system to other types of cancers, especially those difficult to reach by surgery. The scaffold can be engineered to present other functional factors such as CCL21, CCL19, CCR8, and ICAM-1 to provide more realistic conditions of lymph nodes. The artificial lymph node-like scaffold serves as a depot for enhancing CAR-T cell expansion and prolonging the efficacy of cells in vivo, thereby augmenting solid tumor treatment efficacy. The preserved ability of the scaffold could be manipulated by coupling microspheres with other materials that convert the immunosuppressive environment within solid tumors. The study was supported by various funding sources, including the National Natural Science Foundation of China and the National Key R&D Program of China. The authors declared no conflicts of interest, except for Z.G., H.L., and Z.L., who are listed as inventors of a patent related to this research.A three-dimensional scaffold inspired by the physiological process of T-cell proliferation in lymph nodes was developed to enhance the therapeutic effects of chimeric antigen receptor (CAR)-T cells against solid tumors. This scaffold, made from poly(lactic-co-glycolic acid) (PLGA) via microfluidic technique, provides a porous structure with bio-functional stimulatory signals, including anti-CD3, anti-CD28 antibodies, and cytokines, to support the loading, delivery, activation, and expansion of CAR-T cells. The scaffold enables a 50-fold expansion of CAR-T cells in vitro and a 15-fold expansion in vivo. It maintains long-lasting expansion of CAR-T cells for up to 30 days in a cervical tumor model and significantly inhibits tumor growth. The scaffold was modified with T-cell stimulatory signals to mimic the environment of lymph nodes, promoting CAR-T cell proliferation and activity. In vivo studies showed that the scaffold supports sustained CAR-T cell activation and expansion within tumors for up to 30 days. The scaffold was also effective in delaying tumor progression in a xenograft tumor model. The scaffold serves as a CAR-T cell expansion niche in vivo, enhancing CAR-T cell expansion and prolonging their efficacy. The scaffold was found to be safe and could be injected into patients along with prepared CAR-T cells without separation. The scaffold can also be used as a delivery system to load and reserve CAR-T cells. The study demonstrated the therapeutic success in subcutaneous tumors, but further research is needed to apply the system to other types of cancers, especially those difficult to reach by surgery. The scaffold can be engineered to present other functional factors such as CCL21, CCL19, CCR8, and ICAM-1 to provide more realistic conditions of lymph nodes. The artificial lymph node-like scaffold serves as a depot for enhancing CAR-T cell expansion and prolonging the efficacy of cells in vivo, thereby augmenting solid tumor treatment efficacy. The preserved ability of the scaffold could be manipulated by coupling microspheres with other materials that convert the immunosuppressive environment within solid tumors. The study was supported by various funding sources, including the National Natural Science Foundation of China and the National Key R&D Program of China. The authors declared no conflicts of interest, except for Z.G., H.L., and Z.L., who are listed as inventors of a patent related to this research.