5G Communication Networks are today at the stage of maturity of developing key enabling technologies for extended proof-of-concepts (PoC). Although standardization of 5G is yet to be finalized, 5G players already reached a general agreement on key enabling technologies, architecture and deployment scenarios of 5G networks. The 5G community is now looking for translating 5G use cases, vertical industries requirements and ambitions in adopting 5G, into viable business cases. However, the support of 5G new services and seamless connectivity across various vertical industries and very diverse use cases, still requires the integration of multiple access technologies. The 5G ALL-STAR project builds on the outcomes and the cooperation experience of 5GCHAMPION to design, develop, evaluate and trial multi-connectivity based on multiple access, combining cellular and satellite access technologies to support seamless reliable and ubiquitous broadband services. The project will develop a set of technologies and validate system interoperability to provide global connectivity and support mission critical applications of interest in both European and Korean regions. To this end, 5G ALL-STAR will develop selected technologies targeting a set of PoCs to validate and demonstrate in heterogeneous real setup: i) 5G cellular mmWave access system for providing broadband and low-latency 5G services, ii) new radio based feasibility of satellite access for providing broadband and reliable 5G services, iii) multi-connectivity support based on cellular and satellite access, iv) spectrum sharing between cellular and satellite access. In addition, the project will actively contribute to v) global 5G standardization including 3GPP and ETSI focusing on multi-RAT interoperability and New Radio based satellite access, vi) creation of a cross-regional lasting synergy for 5G research, innovation and commercialization through value proposition assessment for vertical industries.