The purpose of this study is to characterize participants with Crohn's Disease (CD) and Ulcerative Colitis (UC) treated with Guselkumab in a real-world setting, and to assess the clinical effectiveness (how well the treatment works) in the overall population and in different participant subgroups. Furthermore patient-reported outcomes like fatigue, health-related quality of life (HRQoL), sexuality, work productivity and activity as well as treatment satisfaction will be assessed.