[80,81] Since this first generation of CAR-constructs, which contained a CD3ζ (or CD3γ) chain alone [82,83,84], costimulatory elements—mostly the intracellular domain of CD28 or 41BB—were added to magnify the signaling effects and induce the more efficient killing of tumor cells [78]. Here, TNFRSF9 is linked to neoplasm.