Thank you for posting your query on Microsoft Q&A, from above description I could understand that you are looking for some used case scenario for using Microsoft 365 DLP policy.
Please do correct me if this is not the case by responding in the comments section.
If yes, then you may use the following scenarios:
Microsoft Purview DLP:
Data loss prevention and Microsoft Teams
Use Endpoint data loss prevention
Use Endpoint DLP Best practice for deploying Just-in-time protection
Use the data loss prevention on-premises Scanner
Sensitivity labels
Use sensitivity labels to protect calendar items, Teams meetings, and chat
Sensitivity labels for Office files in SharePoint and OneDrive
Encryption
Cross-tenant access settings and encrypted content
Conditional Access policies and encrypted documents
Guest accounts for external users to open encrypted documents
Service encryption with Microsoft Purview Customer Key
Thanks,
Akshay Kaushik
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