She received her medical training through a six-year BS/MD program, earning her bachelor's degree at the University of Akron and graduated summa cum laude.

[10][11] The CD22-CAR developed by Mackall's team is also active in large B cell lymphoma[12] and has received Breakthrough Therapy Designation from the US FDA for this indication.

Mackall co-founded CARGO Therapeutics to commercialize the CD22-CAR, now named Firi-cel, which is undergoing Phase II testing in a potentially pivotal trial for patients with large B cell lymphoma.

[13] Working with the Monje lab at Stanford, Mackall developed a GD2-CAR that showed activity in preclinical models of diffuse midline glioma, which are lethal brain tumor occurring primarily in children and young adults,[14] and her group demonstrated that intracerebroventricular delivery of CAR T cells is more potent for treatment of brain tumors in mice than intravenous delivery.

[24] Mackall has led clinical trials of cancer vaccines,[25][26][27] launched the first clinical trial of recombinant human interleukin-7,[28][29] led studies of immune checkpoint inhibitors in pediatric cancers[30][31] and studied a role for bone marrow transplants in pediatric solid tumors.

[32][33] In 2018 Mackall was awarded $11.9 million from the California Institute of Regenerative Medicine to lead a clinical trial using genetically modified T cells engineered to recognize CD19 or CD22 proteins expressed on leukemia or lymphoma.