A common set of questions in the various ConfigMgr forums is how ConfigMgr can work in environments where you either have multiple Azure and Intune tenants, or more commonly, have multiple ConfigMgr primary sites.
Note: When I write multiple ConfigMgr sites, I mean multiple ConfigMgr standalone sites, not sites being part of a ConfigMgr CAS hierarchy.
The ConfigMgr docs is your friend
Support for multiple ConfigMgr sites and Azure/Intune tenants changes over time, so a good source for this information is always the ConfigMgr docs site: https://docs.microsoft.com/en-us/mem/configmgr.
Above being said, here are some common scenarios and what is support in the currently supported ConfigMgr versions (ConfigMgr 2006 – 2103).
Cloud Management Gateway
For the CMG feature, multiple ConfigMgr sites can connect to the same tenant, and deploy separate CMG instances for each ConfigMgr site. For example, in my lab I have ConfigMgr Current Branch site, and a ConfigMgr Technical Preview site. For the CMG feature they are connected to the same tenant, but they have separate CMG instances (and must have separate CMG instanced.
For the Co-Management feature, you can connect multiple ConfigMgr instances to a single Intune tenant. Have I tried it? Nope, I like to keep things simple when I can 🙂
For the Desktop Analytics feature you can have multiple ConfigMgr sites report to a single Azure AD tenant. You can also have different ConfigMgr sites reporting to its own Azure AD tenant (I like that approach).
For more info: Desktop Analytics – Configuration Manager | Microsoft Docs
Happy Deployment, Johan