ArcGIS Hub Basic enables organization members to create customizable sites and pages, share content, collaborate on internal teams, access select initiative templates, integrate surveys, and utilize sharing controls. ArcGIS Hub Basic is included in all ArcGIS Online subscriptions.
With ArcGIS Hub Premium, organizations can create initiatives to get started with pre-designed sites, web maps, and story maps. They can also create custom initiatives to organize content around their unique goals and projects. Initiatives enable staff to invite stakeholders, such as volunteers, partners, students, to the core team. Core teams can also use events, calls-to-action, and messaging to connect with people interested their work. ArcGIS Hub Premium requires an additional purchased license.
Find additional details on the Esri website here.