The implantation of a hyaluronic acid hydrogel containing CAR-T cells targeting human chondroitin sulfate proteoglycan 4, along with polymer nanoparticles encapsulating the cytokine interleukin-15 and platelets conjugated with the checkpoint inhibitor programmed death-ligand 1 (PD-L1), into the tumor cavity of mice with resected subcutaneous melanoma inhibits local tumor recurrence and suppresses the growth of distant tumors through the abscopal effect. Here, CSPG4 is linked to neoplasm.