Chronic rhinosinusitis (CRS) is a highly prevalent disease that imposes a significant socioeconomic burden. Since the emergence of inflammatory endotyping in the mid-2010S, the development of therapeutics targeting specific inflammatory endotypes of CRS has highlighted the need for biomarkers that are non-invasive, accurate, and both biologically and clinically meaningful. Here, we summarized recent updates on biomarkers derived from peripheral blood, nasal tissue, and nasal fluid samples to predict inflammatory endotypes. Furthermore, given that the tendency of recurrence and refractoriness remains a major challenge in the treatment of CRS, predicting clinical outcomes and prognosis before the initiation of treatment is crucial. Therefore, this review also discusses recently identified biomarkers for predicting recurrent and refractory CRS. Through this overview of research findings, we aim to provide insights into the current state of CRS biomarkers and future directions for developing novel biomarkers.