If you use Azure Firewall to protect your resources running on Azure, you will be glad that you can now use new FQDN tags to easily manage access to Office 365 services.
To do so, just edit or create your firewall rules, select the Destination as Service Tags and search for Office 365
This is going to simplify Office 365 access management as when there will be IP addresses or service updates you will not have to maintain anymore your firewall rule; Microsoft will do it for you.