The ambition to facilitate data sharing and interoperability within the Materials and Manufacturing domains was the core motivation for this event. Stemming from the OntoCommons H2020 project activities, this focused workshop provided a platform for academic researchers and industrial practitioners to meet and discuss about the Materials and Manufacturing Commons key enablers, i.e., digital Marketplaces, FAIR Principles and Ontologies. In this workshop, the Digital Marketplaces concept and its current status of implementation was shown in order to continue the discussion about requirements and challenges using ontologies. Tools supporting data documentation and interoperability were showcased, and concrete challenges, success stories, as well as experiences using ontologies were shared.