N-803 Maintenance Therapy Post CAR T-cell Therapy in Patients With Relapsed or Refractory B-cell Non-Hodgkin Lymphomas

Inclusion Criteria: * Subjects aged ≥ 18 years. * Subjects with histologically confirmed B-cell NHL who have received commercially approved CD19-directed CAR T-cell therapy per FDA label * Subjects achieving CR or PR per Lugano Criteria to CAR T-cell therapy on D+30 post-CAR-T. * ECOG Performance Status ≤ 2. * Adequate organ function as defined as: * Hematologic: * Absolute neutrophil count (ANC) ≥750 cells/mm3 (≥0.75 x 10\^9/L) independent of G-CSF support * Platelet count ≥50,000 cells/mm\^3 (≥50 x 10\^9/L) independent of transfusion support * Hemoglobin ≥ 7 g/dL (≥ 70 g/L) independent of transfusion support * Hepatic: * Total Bilirubin ≤ 1.5x institutional upper limit of normal (ULN) or ≤ 3x ULN with Gilbert's disease. * AST(SGOT)/ALT(SGPT) ≤ 3 × institutional ULN ----Subjects with liver metastases will be allowed to enroll with AST and ALT levels ≤ 5 x ULN. * Renal: * Estimated creatinine clearance ≥ 30 mL/min by Cockcroft-Gault formula: * Males: ((140-age)×weight\[kg\])/(serum creatinine \[mg/dL\]×72) * Females: (((140-age)×weight\[kg\])/(serum creatinine \[mg/dL\]×72))×0.85 * For female subjects: Negative pregnancy test or evidence of post-menopausal status. The post-menopausal status will be defined as having been amenorrheic for 12 months without an alternative medical cause. The following age-specific requirements apply: * Women \< 50 years of age: * Amenorrheic for ≥ 12 months following cessation of exogenous h…