Adoptive cellular immunotherapy with anti CD19 chimeric antigen receptor (CAR)-T 
cell has changed the treatment landscape in relapsed/refractory B cell 
lymphomas. They have emerged as effective therapy in patients with multiple 
relapsed/refractory disease, capable of sustaining durable remissions. Two CAR-T 
cell products (axicabtagene ciloleucel and tisagenlecleucel) are currently 
approved by the United States Food and Drug Administration. A third anti CD19 
CAR-T cell, lisocabtagene ciloleucel is currently being evaluated in large 
clinical trials and may also be United States Food and Drug 
Administration-approved soon. CAR-T cell-related toxicities, including 
infections, cytokine release syndrome, and neurotoxicity are potential 
complications of therapy. With increasing use of CAR-T cells, the mechanism of 
toxicities and mitigation strategies needs to be developed. Additionally, 
reasons for CAR-T cell failure and progression following this therapy needs to 
be further studied. We describe the recent developments in this field, with 
emphasis on the complications of therapy and factors contributing to toxicities, 
efficacy, and resistance. We also describe the ongoing research in this field 
and the newer CAR-T cell constructs that are being developed to counter the 
challenges that have been identified in this field.