IL9 and chronic rhinosinusitis with nasal polyps: Notably, approximately 85% of patients with CRSwNP exhibit eosinophilic or type 2 inflammation (Bachert et al., 2021), marked by elevated levels of interleukins (IL) such as IL-4, IL-5, IL-9, IL-13, IL-25, and IL-33 (Bachert and Akdis, 2016).