Initial preclinical studies with first- and second-generation CARs targeted solid tumor-associated antigens, including disialogangliosides (GD2, GD3), carcinoembryonic antigen (CEA), and PSMA.39 However, Sadelain and his team shifted their focus to hematological malignancies, proposing CD19 as a promising antigen nearly 15 years before its clinical implementation in CAR-T therapy.84 In a landmark 2003 study, the MSKCC team demonstrated the feasibility of expanding CAR-T cells ex vivo using artificial antigen-presenting cells and IL-15. The gene discussed is CEACAM5; the disease is hematologic disorder.