In the last few months, another therapeutic approach for CRSwNP has emerged, namely mepolizumab, an anti-IL-5 monoclonal antibody that regulates the eosinophil activity, decreasing the blood and tissue eosinophil counts, and it is approved for severe eosinophilic asthma (SEA), eosinophilic granulomatosis with polyangiitis (EGPA), hypereosinophilic syndrome (HES) and CRSwNP [19]. Here, IL5 is linked to hypereosinophilic syndrome.