Microsoft announced that a new security feature dubbed Safe Documents will be available in private preview for Office 365 ProPlus customers starting today. Microsoft also announced that it is significantly expanding its private preview to become generally available during the summer of 2020. The feature is designed to automatically check Microsoft Office documents against known threat profiles and risks before allowing the users to open them. Microsoft is also working on new features that will block malicious content in Office 365 regardless of custom tenant configurations unless manually overridden. Microsoft previously announced the rollout of the Office 365 Advanced Threat Protection (ATP) feature.
Source: https://www.bleepingcomputer.com/news/security/office-365-users-get-automated-protection-from-malicious-docs/