M365 GCC High includes many of the same feature sets and products of the commercially available Microsoft 365 (Microsoft 365 Commercial): SharePoint Online, Teams, Exchange Online, OneDrive for Business, etc. However, full parity is not achieved. One notable example is found within Microsoft Teams for O365 GCC High. Unlike the Commercial offering of Microsoft 365, Audio Conferencing for Teams US Government does not include dial-in phone numbers and the underlying configuration in Azure Government to enable the capability. A solution is required for direct inward dial through Direct Routing to allow users to create meetings with Teams Dial-in conference numbers.
Enterprise Mobility + Security for US Government
Microsoft's Enterprise Mobility + Security, or EMS, offerings for US GCC High and DOD customers are built on the Microsoft Azure Government cloud and are designed to inter-operate with the Microsoft 365 GCC High and DOD environments. The EMS E5 suite is available for both GCC High and DoD customers, however Microsoft Cloud App Security and Azure Advanced Threat Protection are available only to GCC High customers. Azure Active Directory P1/P2, Microsoft Intune, Azure Information Protection P1/P2, Microsoft Cloud App Security, and Microsoft Defender for Identity are certified FedRAMP-High. (The security product previously known as Azure Advanced Threat Protection is now known as Microsoft Defender for Identity.
Organizations that use EMS for US Government GCC High and DOD offerings benefit from the following features:
Your organization's customer content is physically segregated from customer content in Microsoft's commercial services.
Your organization's customer content is stored within the United States.
Access to your organization's customer content is restricted to screened Microsoft personnel.
Compliance with certifications and accreditations that are required for US Public Sector customers, including DoD Security - Requirements Guidelines, DFARS, and International Traffic in Arms Regulations (ITAR)
Azure Information Protection Premium Government
Azure Information Protection (sometimes referred to as AIP) is a cloud-based solution that helps an organization to classify and optionally, protect its documents and emails by applying labels. Labels can be applied automatically by administrators who define rules and conditions, manually by users, or a combination where users are given recommendations.
You use Azure Information Protection labels to apply classification to documents and emails. When you do this, the classification is identifiable regardless of where the data is stored or with whom it’s shared. The labels can include visual markings such as a header, footer, or watermark. Metadata is added to files and email headers in clear text. The clear text ensures that other services, such as data loss prevention solutions, can identify the classification and take appropriate action. There are known gaps between AIP Premium commercial and GCC High/DoD that can be found here.
Microsoft Defender for Office 365
Microsoft Defender for Office 365 is a cloud-based email filtering service that helps protect your company against unknown viruses and malware by providing substantial zero-day protection and includes features to protect your company from harmful links in real time. These capabilities are critical to meeting the NIST 800-171 control family 3.14 System and Information Integrity. Although, it is important to understand Defender for Office 365 cannot simply meet compliance requirements by 'turning it on'.
The Defender for Office 365 license has powerful reporting and URL trace capabilities that give administrators insight and clarity into the kind of attacks happening in your organization. The reporting capabilities, moreover, can cover the "actions of individual system users [to] be uniquely traced to those users so they can be held accountable for their actions" (NIST 800-171). Defender for Office 365 covers most Exchange architectures – rather on premises, Exchange Online, or Hybrid if configured properly.
Hope this information helps.