Asthma and chronic rhinosinusitis (CRS) are inflammatory diseases of the respiratory tract, asthma from the lower part, and CRS, from the upper part. In theory, these parts are correlated as if they are one single organ, namely united airways, which means that if one is affected by any condition, the other might be impacted as well. However, this relationship has not yet been described down to the cellular and molecular levels. By investigating patients that have (1) asthma and CRS with nasal polyp, (2) asthma and CRS without nasal polyp, and (3) just CRS with nasal polyp, we aim to determine the correlation of the upper and lower part of the respiratory tract. At first, the characterization of disease will be determined by established clinical criteria, such as lung function, blood analysis for the presence of eosinophils (a type of white cells), and nasal polyp score. To continue, in-depth analysis of nose, oropharynx, and lung samples will help gain information about the inflammatory profile and local microbiome of the three different groups of patients through molecular and cellular assays. The results of this study will help to describe the hypothesis of the united airways which will provide better guidance for medical treatment of asthma and CRS with or without polyp, thus improving the life quality of patients.