Windows is helpful for administering and maintaining users on Active Directory. This goes doubly if you are running Windows on all employee computers. Linux is powerful and lightweight and can manage users from a variety of operating systems. It really depends on the use case, but Linux does well for servers that act as the backbone of a network.
If you’re expecting to have a lot of users and need an operating system that scales well, Linux is the way to go for your servers. If you have a plethora of Windows machines and just need something to provision a network while keeping track of everyone on it.