A monoclonal antibody directed against the negative immunoregulatory human cell surface receptor programmed death-1 (PD-1, PCD-1,) with immune checkpoint inhibitory and antineoplastic activities. Upon administration, anti-PD-1 monoclonal antibody SHR-1210 binds to and blocks the binding of PD-1, expressed on activated T-lymphocytes, B-cells and natural killer (NK) cells, to its ligands programmed cell death ligand 1 (PD-L1), overexpressed on certain cancer cells, and programmed cell death ligand 2 (PD-L2), which is primarily expressed on antigen presenting cells (APCs). This prevents the activation of PD-1 and its downstream signaling pathways. This restores immune function through the activation of cytotoxic T-lymphocytes (CTLs) and cell-mediated immune responses against tumor cells or pathogens. Activated PD-1 negatively regulates T-cell activation and plays a key role in tumor evasion from host immunity.