Defender for Business (preview)

I’m having a hard time to get around the licensing model regarding Defender for Business (preview), that will be released soon.

This this a license that you need to buy if you have MS business premium licenses?

if not what version is included in in business premium?

On the following page Microsoft compares Defender for Business (preview) with Defender for endpoint plan 1 and 2 …..  they also write When Defender for Business becomes generally available, it will be included in Microsoft 365 Business Premium. What will happen with this product and will it be included in business premium?

https://docs.microsoft.com/en-us/microsoft-365/security/defender-business/compare-mdb-m365-plans?view=o365-worldwide