CTLA4 and neoplasm: Immune checkpoint inhibitors (ICIs) are monoclonal antibodies that target crucial negative regulators of the immune system, mainly cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), programmed cell death protein 1 (PD-1), and PD-1-ligand (PDL-1), leading to enhanced anti-tumor immune responses, but also triggering toxicities that may affect any organ and are defined immune-related adverse events (1).