Microsoft is working on improving the suspicious content submission experience for admins in all Microsoft 365 environments, as well as enhancing the Quarantine file previewer. Microsoft 365 is a software bundle which provides three lines of subscriptions, namely Office 365, Windows 10, and EMS (short for Enterprise Mobility + Security) The changes will be rolled out during September 2019. Microsoft also rolled out better analysis capabilities for Office 365 last month, allowing admins with access to Threat Explorer to both preview and download malicious emails for further examination.
Source: https://www.bleepingcomputer.com/news/security/microsoft-365-to-get-enhanced-suspicious-content-submission/