Include whatever permissions are necessary to access the newer Teams & Skype admin center in the Skype for Business Administrator role.
There is a AAD role for Skype for Business Administrator, but it doesn't work properly with the new Teams & Skype admin center in O365. You have to do a PIM request for Global Admin to get to it.
Jonathan Christie commented
Azure AD now has the following roles that you can use:
Teams Service Administrator
Teams Communications Administrator
Teams Communications Support Engineer
Teams Communications Support Specialist