Autologous T cells engineered with a chimeric antigen receptor targeting CLDN18.2, augmented with an NKG2D receptor–based module that provides additional co-stimulation via recognition of NKG2D ligands (MICA/B, ULBPs). CAR engagement activates T-cell signaling and, together with NKG2D co-stimulation, drives T-cell activation, cytokine release, and cytolytic killing of CLDN18.2-positive tumor cells.