To apply Microsoft Defender for Endpoint antivirus policies to the macOS devices, you need to install Defender for Endpoint on the devices. You can use Intune to deploy a script that installs Defender for Endpoint on macOS devices. After installation, you can use Intune to create and assign antivirus policies to the devices. Reference: https://docs.microsoft.com/en-us/windows/security/threat-protection/microsoft-defender-atp/mac-install-with-intune