The success of CAR-T targeted to CD19 for B-cell acute lymphocytic leukemia (B-ALL)37 and the availability of one single-cell B-ALL data set (GSE132509, “Methods”)38 allowed us to assess further whether our 0.8 killing threshold for malignant cells reasonably captures the success observed in a human trial. The gene discussed is CD19; the disease is precursor B-cell acute lymphoblastic leukemia.