The in vivo results confirmed that the combination of CEA CAR T cells with rhIL-12 significantly enhanced their antitumor activity in terms of growth inhibition of the newly colonized colorectal cancer cell line HT-29, the pancreatic cancer cell line AsPC-1, and the gastric cancer cell line MGC803 compared with CEA CAR T-cell therapy alone. Here, CEACAM5 is linked to gastric cancer.