There's no simpler way to say it than this: In the cloud, Identity is the new control plane. This fundamental principal of security and management means that securely connecting users to applications and resources (no matter where they exist or how they are used) is what will set apart world-class organizations.
This huge shift in how we approach IT is embodied by Azure AD. Azure AD allows you to seamlessly link your users, devices, and applications – across both cloud and on-premises environments. Bringing your devices to Azure AD enables you to take advantage of Azure AD's full potential to better improve productivity for your users and security for your resources. Having devices in Azure AD is the foundation for both Co-Management and device-based conditional access.