Autologous T cells are engineered ex vivo to express a chimeric antigen receptor (e.g., targeting CD19 or BCMA) that recognizes tumor antigens independently of MHC. After lymphodepletion, the CAR T cells are reinfused; antigen engagement triggers CD3ζ and costimulatory (e.g., CD28 or 4-1BB) signaling, driving T‑cell activation, proliferation, cytokine release, and cytotoxic killing of target cells via perforin/granzyme pathways, with in vivo expansion and persistence mediating antitumor effects.