Prior to DLP in Microsoft 365 compliance center, most organizations protected data using the transport rules aka mail flow rules created in Exchange admin center. You can use transport rules to identify and act on messages that flow through the Exchange Online organization. With the evolution of a centralized console for all the workloads, it’s recommended to move the existing Exchange admin center-DLP policies to DLP in Microsoft 365 Compliance Center. To learn more about Data loss prevention, please referDLP.
Advantages of migrating to Compliance Center:
Unified admin console which is easy to maintain
Single policy across all workloads (Exchange, SPO, ODB, Teams, Devices, MCAS, etc.)
Protection of data at rest and in transit.
Near real-time alerts
Easy navigation to other compliance product features and capabilities
More advanced classification and labeling
Rich built-in alerting and incident management experience