Here, we analyzed the prevalence of LAG3 rs870849 in B-cell lymphoma patients and the treatment outcomes according to the LAG3 genetic background and discovered that LAG3 germline variants may affect the risk of developing lymphoma and also affect the treatment outcome of DLBCL patients in the current CD19 CAR-T cell therapies. Here, CD19 is linked to B-cell non-Hodgkin lymphoma.