While IL-9 exacerbates lung injury in COPD mice by increasing inflammatory and oxidative stress [57] and airway inflammation associated with SARS-CoV-2 infection [58], it protects against bleomycin-induced lung injury [59] and has a protective role in sepsis-induced lung injury by reducing macrophage apoptosis and M1 polarization [60]. The gene discussed is IL9; the disease is chronic obstructive pulmonary disease.