Etiology of Acute Exacerbations of Chronic Obstructive Pulmonary Disease (AECOPD) in Japan

Inclusion Criteria: * Participants must be able and willing to comply with the requirements of the protocol. * Participant must be aged greater than or equal to (\>=)40 years to to less than or equal to (\<=)80 years at the time of signing the informed consent form (ICF). * Participants must have a record of a clinical diagnosis of COPD, ACOS or CB. * Participants must have moderate to severe airflow limitation based on spirometry: FEV1 percent predicted normal \>=30 to \<=80 percent (%) and post-bronchodilator FEV1/forced vital capacity (FVC) ratio \<0.7. * Participants must be symptomatic at Screening, defined as having a CAT score \>=10. * Participants must have a documented history of at least 1 LRTI treated with antibiotics and/or oral/systemic corticosteroids. * Participants must be current or former tobacco (cigarette) smokers with a smoking history of \>=10 pack-years. * Participants may be male or female. For female participants: A female participant is eligible to participate if she is not pregnant or breastfeeding. Women of non-childbearing potential can also participate. A woman of childbearing potential must have had a highly sensitive negative urine pregnancy test. * Participants should be able to provide a spontaneous or induced sputum sample of \>=0.2 grams (g) at the Screening Visit. Exclusion Criteria: * Participants with a diagnosed respiratory disorder other than COPD, ACOS or CB. * Participants with a diagnosis of alpha-1 antitrypsin deficiency as the …