Hi,
Roadmap for future maybe not exists, there is a page that shows the lifecycle of the current Windows Server/Client releases:
Windows Server release information
https://learn.microsoft.com/en-us/windows-server/get-started/windows-server-release-info
Windows Client lifecycle fact sheet
https://support.microsoft.com/en-us/help/13853/windows-lifecycle-fact-sheet
Windows message center: https://learn.microsoft.com/en-us/windows/release-information/windows-message-center
I hope this information above can help you.