The Efficacy of Fluticasone Furoate/Vilanterol/Umeclidinium Compared With Vilanterol/Umeclidinium in Reducing Air Trapping and Airway and Blood Cytokine Levels in COPD

Inclusion Criteria: * Patients who have met the criteria for COPD GOLD B defined by an exacerbation not more than 1 time in the last year prior to the study enrollment. These patients will be recruited in sequential sequence. * Patients with COPD GOLD B are previously treated with either LAMA or LAMA/LABA or short-acting bronchodilators * Patients who are able to provide informed consent. Exclusion Criteria: * \- Concomitant with active and old pulmonary TB, lung cancer, bronchiectasis, lung fibrosis, destroyed lung, other malignancy, active heart diseases. * Receiving long-term treatment with immunosuppressive drugs and systemic corticosteroids * Being treated with triple therapy (ICS/LABA/LAMA) * Being in terminally ill conditions