58 reported the outcomes of 15 patients with r/r B‐cell malignancies treated with autologous anti‐CD19 CAR T cells incorporating both CD28 and 4‐1BB costimulatory domains, four of whom did not receive lymphodepletion before CAR T cell infusion. Six achieved a CR, two of four with B‐ALL and four of 11 with B‐NHL. No treatment‐related mortality was reported, and three cases of severe CRS or neurotoxicity were observed, comparable to the toxicity rates observed with second‐generation CAR T cell therapies.36, 58, 59. This evidence concerns the gene CD28 and acute lymphoblastic leukemia.