Another important target in immunotherapy is represented by the immune checkpoint PD-1/PD-L1 PD-1 is an inhibitory receptor expressed by activated T cells, B cells, natural killer (NK) cells and myeloid cells, which binds to PD-L1, a cell surface glycoprotein of the B7 family primarily expressed on antigen-presenting cells, activated T cells, and stromal or tumor-infiltrating immune cells. The gene discussed is CD274; the disease is neoplasm.