Interestingly, the IL‐12‐producing CAR‐T cells can also inhibit tumour growth of CEA‐negative MC38 cells when these cancer cells are co‐injected with CEA‐positive C15A3 cells, and such suppressive effects disappear with anti‐TNF‐α‐neutralizing antibody treatment. The gene discussed is CEACAM5; the disease is neoplasm.