PDCD1 and lymphoma: ,81 Using gene editing, PD-1 knockout in CAR-T cells that were redirected against the B cell marker cluster of differentiation 19 (CD19)82 and membrane proteins mesothelin83 and MUC1,84,85 which are upregulated in a range of malignancies, are investigated in clinical trials for the treatment of B cell leukemia/lymphoma,82 multiple mesothelin-positive solid tumors (such as pancreatic cancer, cholangiocarcinoma cancer, and ovarian cancer),83 esophageal cancer,84 and lung cancer.85