IL-18 secretion by CAR-T cells may shift the immunosuppressive tumour environment to a pro-inflammatory state by increasing the activation of CD11b+Gr1– macrophages and MHC-II+CD11c+ dendritic cells at the tumour site and systemically, especially in SCLC, which contains a large number of macrophages. The gene discussed is IL18; the disease is small cell lung carcinoma.