The Humanities and Cutural Heritage Open Science Cloud (H2IOSC) project aims to create a federated network of Italian nodes to support four European Research Infrastructures in the Humanities and Cultural Heritage sectors: DARIAH, CLARIN, OPERAS, and E-RIHS. By integrating digital resources, physical instruments, archives, and data services, H2IOSC seeks to advance data-driven research and digital transformation across cultural and creative fields, aligning with FAIR principles for data accessibility.Within the project, the Institute of Heritage Science (CNR-ISPC) is instrumental, particularly its Milan branch, which leads Task 4.10 focused on “Resources Interoperability: DIGILAB Resources (E-RIHS)” as part of Work Package 4 (WP4). This task emphasizes the mapping of formats, standards, and ontologies essential for Heritage Science, aiming for cross-domain integration and semantic interoperability through DIGILAB—a collaborative platform for data sharing and virtual research in Heritage Science. Key outputs include a semantic mapping of resources and the development of a specialized Heritage Science ontology compatible with international standards like CIDOC CRM. An annex, developed by ISPC’s Lecce branch, further supports interoperability for pilot projects in WP7, with specific applications in illuminated manuscript and diagnostic ontology extensions.