Next after that is running VDIs on either a small Citrix farm on Azure or as Desktop as a Service, since AD, SSO, 2FA ,Productivity tools and user file storage is there.
After that, you already have some firewalling and VPNs in place so adding the odd server is just a step away.
Adding dedicated lines and firewalls and rules and all bella and whistles with all four big players (AMZ, IBM, MSFT, GOOG) plus 2 ISPs adds cost fast, so you typically pick 2. MSFTbis already there for O365 so yeah, they have a head start
After that, you already have some firewalling and VPNs in place so adding the odd server is just a step away.
Adding dedicated lines and firewalls and rules and all bella and whistles with all four big players (AMZ, IBM, MSFT, GOOG) plus 2 ISPs adds cost fast, so you typically pick 2. MSFTbis already there for O365 so yeah, they have a head start