CTLA4 and myelodysplastic syndrome: The first ICPi molecules challenged in clinical trials for HR-MDS patients are ipilimumab [134,135,136] (CTLA-4 inhibitor), nivolumab [137,138] or pembrolizumab [139,140] (PD-1 inhibitors), and atezolizumab or durvalumab [141,142,143] (PD-L1 inhibitors).