RecruitingPhase 2Drug trialCAR-T Cell Therapy, Mosunetuzumab and Polatuzumab for Treatment of Refractory/Relapsed Aggressive Non-Hodgkin's Lymphoma (NHL).The purpose of this research study is to test if a combination treatment of chimeric antigen receptor (CAR) T-cell therapy, Mosunetuzumab, and Polatuzumab Vedotin will result in tumor reduction.