CEACAM5 and cancer: The scFv is widely adopted in CAR construction due to its compact size, high affinity and specificity for antigen recognition.77 By changing the scFv, CARs can specifically recognize different antigens on various cancer cells (e.g., cluster of differentiation 19 (CD19), mesothelin, CEA, B-cell maturation antigen (BCMA), CD38) by one-to-one authentication,39 and subsequently activate cancer-killing of CAR T cells.