CEACAM5 and neoplasm: Boolean logic gating switches are the mathematical operators “IF/THEN,” “AND,” “OR,” and “NOT.” The use of logical gating switches in CAR-T-cell design can further control their activation, improve the specificity of cell killing, and reduce toxic side effects.71 Logically gated CAR-T cells targeting carcinoembryonic antigen and mesothelin showed specific toxicity against tumor cells expressing both antigens, without affecting the growth of single antigen-positive tumor cells.133