Li et al. [76] reported the use of pembrolizumab (n = 13) or nivolumab (n = 1) in patients aged 4–17 years with relapsed B-ALL (n = 13) or B lymphoblastic lymphoma (n = 1)14 days or later after anti-CD19-directed CAR T infusion. This evidence concerns the gene CD19 and acute lymphoblastic leukemia.