Linking project data and data from routine clinical practice with healthcare-related data is essential for German healthcare research in order to answer complex questions validly and efficiently. Currently, fragmented data sources, heterogeneous legal requirements, and a lack of infrastructure prevent the optimal use and linking of these data. The Network University Medicine (NUM) is therefore developing a dedicated data infrastructure to link primary study data and routine clinical data with external healthcare-related data (e. g., data from statutory and private health insurance companies, data from cancer registries of the federal states, and data from registration offices). The position paper describes the various data worlds, including examples from epidemiological and clinical research that illustrate the added value and challenges of data linkage. In particular, it presents the new structures of the data acceptance and processing center (DAAeD) in the NUM, which is intended to enable quality-assured, data protection-compliant receipt and linkage of data. Standardized application and approval procedures as well as innovative privacy-preserving record linkage procedures are central to this. International experience, including from Scandinavia and the UK, demonstrates the benefits of such infrastructures for research and healthcare. In conclusion, we advocate rapid political and institutional implementation of the recommendations described in order to make health research in Germany competitive in international comparison and to ensure sustainable, patient-centered health care.