Immune checkpoint inhibitors targeting the programmed death 1/programmed death-ligand 1 (PD-1/PD-L1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) pathways have shown significant antitumor activity, tolerable safety profiles, and durable, long-term responses in relation to different cancers, including in metastatic urothelial carcinoma patients [180,181,182]. Here, CTLA4 is linked to cancer.