CTLA4 and renal cell carcinoma: Approved targeted therapy agents in advanced and metastatic RCC include bevacizumab (a monoclonal antibody that prevents vascular endothelial growth factor (VEGF)-A binding to its receptor), tyrosine kinase inhibitors (TKIs, that directly inhibit the VEGF receptor), inhibitors of the mammalian target of rapamycin (mTOR) complex (i.e., temsirolimus, everolimus), and immune checkpoint inhibitors against programmed cell death protein-1 (PD-1) (nivolumab) and against cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) (ipilimumab).