Am a keen follower of Microsoft's SharePoint Blog and proud to provide this direct from the Microsoft Tech Community:

This week at Microsoft Ignite we announced the new home site app. The app gives employees a gateway to your organization, starting with the app’s name and icon, which you can customize to reflect the identity of your organization or your intranet. The app’s multi-level navigation lets people find sites across the organization, including portals, teams, communities and applications.

We are happy to see the excitement for this in the community and with our customers. Many of you have asked for additional information. As part of Ignite we have released a new session, on demand, focused on the home site app.

We have also put together an FAQ with the most common questions we have been asked.

Home site app

Q: Can any site be pinned as a Home site app in Teams? 

A: Communication sites designated as Home Sites are eligible for pinning in Teams as the Home site app using our default configuration flow. 

Q: Where are global navigation links curated? 

A: Links for global navigation are managed through the home site, by home site owners, freeing global admins from having to play the role of curator 

Q: Can my classic site be pinned in Teams ? 

A: Only home sites are eligible to be pinned as the home site app in Teams with our default configuration flow.  Home sites must be modern SharePoint communication sites. 

Q: What is difference between Home site app and Home page pinned as tab? 

A: The home site app provides organizations to pin company branded entry point to their intranet as a top level app in Teams.  It provides an immersive site consumption experience, complete with navigation, mega-manus and support for tenant wide search.  It also provides quick access to company curated resources, important sites and news similar to those provided by the SharePoint App Bar in the web.  Home pages (or any other SharePoint pages) pinned as tabs in Channels provide ways to bring content directly into Team collaboration scenarios, and these pages have navigation and search elements removed to facilitate focus on the page content itself. 

Q: Do I need a Home site app for the Global nav to show up in Teams? 

A: Yes, the global navigation links are stored in the home site of a tenant, and is required in order for the navigation panel to appear in the home site app in Teams 

Q: Can a Team site be a Home site? 

A: No. Only communication sites can be made a Home site in a tenant. 

We are humbled and honored by the reaction to this upcoming feature and appreciate all the engagement with us. Please, keep your feedback and questions coming.

The above is kindly provided by the Microsoft Tech Community!