The disclosure provides cells comprising CD19-directed chimeric antigen receptor (CAR) genetically modified autologous T cell immunotherapy for the treatment of, e.g., relapsed or refractory large B-cell lymphoma after two or more lines of systemic therapy, including diffuse large B-cell lymphoma (DLBCL) not otherwise specified, primary mediastinal large B-cell lymphoma, high grade B-cell lymphoma, and DLBCL arising from follicular lymphoma. Some aspects of the disclosure relate to methods of treatment and monitoring following infusion of T cell therapy provided herein.