In a CD-19 CAR-T study of relapsed/refractory diffuse large B-cell lymphoma (215), 6 patients who progressed following CD19-CAR-T therapy, were given CAR-T cells engineered with CSR PD1ex-CD28in, of which 3/6 patients achieved complete remission, and 1/6 achieved partial response. This evidence concerns the gene CD19 and diffuse large B-cell lymphoma.