• Age \> 18 years

• Subject must be able and willing to provide informed consent. In the case where the patient is incapacitated or not otherwise capable, a legally authorized representative (or decision maker when there is not an advanced directive in place) must be willing to provide informed consent on behalf of the patient.

• Able to comply with the study protocol, in the investigator's judgment

• ECOG PS of 0 - 2

• Pathology report confirming eligible diagnosis

• Documented CD20+ tumor cells on most recent biopsy

• Patients will have failed to respond to frontline standard of care therapy containing an anthracycline and anti-CD20 antibody

• Patients will be eligible and consent to be treated with a commercially available anti-CD19, 4-1BB, CD3zeta CAR-T cell therapy or anti-CD19, CD28, CD3zeta CAR T cell therapy (for example, tisagenlecleucel, lisocabtagene maraleucel, or axicabtagene maraleucel)

• Patients must have a PET/CT scan (preferred), diagnostic CT scan, or MRI with at least one bi-dimensionally measurable lesion (≥ 1.5 cm for nodal lesions or ≥ 1cm for extra-nodal lesions in largest dimension by low-dose computerized tomography \[CT\] scan with FDG-uptake ≥ liver)

• Adequate laboratory studies

• Resolution of toxicities from prior therapy to a grade that does not contraindicate trial participation in the opinion of the investigator

• Ability and willingness to take proper contraceptive precautions