PDCD1 and acute lymphoblastic leukemia: in a case study on one B-precursor ALL patient who was resistant to treatment with blinatumomab (a CD19/CD3 bsAb antibody) demonstrated that, after blinatumomab treatment, PD-L1 expression was increased on the tumor cells, suggesting combination of BiTE therapy with programmed cell death protein 1/programmed death-ligand 1 (PD-1/PD-L1) inhibitors could be beneficial for managing tumor immune escaping mechanism (53).