About 18 months ago, Microsoft has announced the integration of Intune service into the Azure ARM portal.
Now, the Intune Silverlight portal is going to be removed (starting August 31st, 2018) with all Intune capabilities moved to the Azure ARM portal.
If you are still using the Intune agent to manage Window 7 (and later), the Silverlight portal will remain available. This will be the only workload remaining in this legacy portal. All other management workloads (Windows 10, mobile device management…) will be available within the Intune capabilities in the Azure ARM portal.
If you are not yet using Intune with the Azure portal, you should start familiarizing yourself and also starts taking advantage of the advanced capabilities of this integration like Conditional Access.