Therapy with chimeric antigen receptor T (CAR-T) cells has demonstrated activity against refractory hematologic malignancies, however not all tumors respond or remain in response to CD19 targeted CAR-T cells. We posit that CAR-T cells expressing BAFF (BAFF CAR-T cells) can become another strategy to treat refractory hematologic malignancies, even after relapse following cluster of differentiation antigen 19 (CD19) targeting CAR-T treatment. This phase 1 study will evaluate safe dose and provide initial signal of the activity of BAFF CAR-T cells against refractory hematologic malignancies using a single lymphodepletion regimen and using a BAFF CAR-T cell manufacturing process.