Shah et al., who developed a novel CD22-targeted/4-1BB CAR T-cell and tested it in a phase I dose–escalation trial in children and young adults with R/R CD22 hematologic malignancies, described a dose-dependent antileukemic response in CD19-negative/dim or CD191 relapsed ALL patients with an acceptable toxicity profile that included limited CRS, minimal neurotoxicity, and an effective signal that was not altered by earlier CD19 targeting. The gene discussed is CD22; the disease is hematologic disorder.