<h4>Background</h4>Antigen escape and PD-L1/PD-1 axis-mediated immunosuppression in the tumor microenvironment (TME) are the predominant drivers of treatment failure in adult patients with relapsed/refractory (R/R) B-cell acute lymphoblastic leukemia (B-ALL). The gene discussed is CD274; the disease is acute lymphoblastic leukemia.