Threat Explorer and Investigations: Useful Microsoft Defender for Office 365 Features
Microsoft Defender for Office 365 (plan 2) contains the Threat Explorer feature. It's a useful way to investigate problematic messages which arrive in a tenant. The automated investigations feature can highlight messages containing malware by assembling evidence about warning signs in the message or its contents, and administrators can then action the recommendations up to and including the removal of messages already delivered to user mailboxes. Automating investigations is a good thing, if you afford Defender for Office 365 Plan 2.