RecruitingDevice studyOptimizing ctDNA-based MRD Assessment in DLBCL, MCL, and FL Patients Undergoing CAR TherapyIn this study, invesigators propose to analyze 150 DLBCL patients, 50 MCL patients, and 100 FL patients to determine the clinical utility of ctDNA- as well as circulating tumor cell (CTC)-based MRD assessment in CAR therapy patients. The project detailed in this protocol will utilize the clonoSEQ platform as specific quantification of residual DLBCL/FL/MCL and correlate its results with radiologic assessment of disease and clinical outcomes. Invesitgators predict there will be a strong correlation between ctDNA and PET/CT and dynamic changes in ctDNA will precede radiologic evidence of disease recurrence in patients following CAR therapy.