PDCD1 and neoplasm: Rupp et al. reported that CRISPR-Cas9-mediated Pdcd1 (PD-1) suppression in anti-CD19 CAR T-cells augments their effectiveness in destroying cancer cells in vitro using Human CD19 K562+ myelogenous leukemia cell line as a model, and also improves PD-L1+ tumor clearance in mouse xenograft models [106].