PDCD1 and neoplasm: The evasion of tumor cells from immunorecognition was associated with elevated expression of immune checkpoint molecules such as programmed cell death-1 (PD-1, CD279), its ligand PD-L1 (CD274), cytotoxic T-lymphocyte associated protein-4 (CTLA-4, CD152), or the cell surface molecule B7-H3 (CD276) [16].