You can now get the device group memberships from the Intune/Endpoint Configuration portal.
To get this information just connect to your Intune portal (https://endpoint.microsoft.com/) and access the Devices blade to either filter by OS (Windows, iOS/iPad, Android) or go to the All devices blade
Then just click on the device you want to get the memberships and reach the Group membership blade
This new capability is quite helpful when your Intune/Endpoint Configuration Manager don’t have access to the Azure AD portal to check the groups the device belongs to.