CD274 and neoplasm: Atezolizumab is a tumor immunotherapy monoclonal antibody that, unlike tumor immunotherapy against PD-1, can activate T cells by binding to PD-L1 protein on the surface of tumor cells and on the surface of tumor-infiltrating immune cells, blocking the binding of PD-L1 to PD-1 and B7.1 receptor and prompting the human immune system to recognize and attack tumor cells [19].