PDCD1 and cutaneous mastocytosis: Immunotherapy treatments based on the immunologic checkpoint inhibitors programmed death cell protein 1 (PD-1) and cytotoxic T-lymphocyte antigen 4 (CTLA-4), such as nivolumab or ipilimumab, have been a main breakthrough in the treatment of CMM and have changed the landscape of treatment options for CM in recent years [12].