CD247 and neoplasm: Compared to the first-generation CAR-T cells with only CD3ζ-STD (1st STD), the second-generation CAR-T cells with CD3ζ-STD and 2nd STD derived from various co-stimulatory molecules are superior in their abilities to proliferate, produce cytokines and to persist in vivo, and they exhibit more potent anti-tumor activity [17,18,19,20,21,22].