In the CLL 4 trial, CD19 CAR T-cells were used as a single agent, resulting in an ORR of 82%, with a 45% CR and a high rate of uMRD observed in heavily pre-treated CLL patients, including high-risk patients who were refractory to BTKi and venetoclax [95]. The gene discussed is CD19; the disease is B-cell chronic lymphocytic leukemia.