CTLA4 and renal cell carcinoma: After the first regulatory approval of an ICI, the anti-cytotoxic T lymphocyte antigen 4 (anti-CTLA-4) agent ipilimumab, several anti-programmed death (ligand) 1 (anti-PD-(L)1) agents—pembrolizumab, nivolumab, atezolizumab, avelumab, durvalumab, and cemiplimab—have been approved for the treatment of patients with different types of cancer, including advanced/metastatic non-small cell lung cancer (NSCLC), renal cell carcinoma (RCC), and melanoma (2).