As you should probably know now, the Microsoft Store for Business (MSfB) is being retired (https://t.co/j8Tcvm1gGO).
As you also probably know, it was not possible to delete (legacy) Microsoft Store for Business applications from Intune; you had to do it from the Microsoft Store for Business portal.
That said you can not remove all MSfB applications as you need to have at least one application to maintain the synchronization between MSfB and Intune.
This means will still have at least one ‘legacy’ MSfB application left in Intune.
Well, good news as you can now delete these ‘legacy’ MSfB applications directly from the Intune portal, even if they are still assigned.