Fig. 1From: Current advances and challenges in CAR T-Cell therapy for solid tumors: tumor-associated antigens and the tumor microenvironment Four generations of CAR T cells. ​An overview of the four generations of CARs displayed on the surface of a T-cell while contacting their antigens on a tumor cell. scFvs that act as ligand-binding domains in CARs mediating tumor cell recognition are shown in red, with VH and VL domains connected to intracellular signaling domains via a hinge and a transmembrane domainBack to article page