Newbie question: When will the next minor point (dot) and full, major release be for Debian?

Newbie question: When will the next minor point (dot) and full, major release be for Debian?
Thanks

Both 9 and 10 just had a point release update.

https://www.debian.org/News/

No release date has been scheduled for version 11 yet.

Why is there a version 9 and a version 10 both being offered concurrently?

The developers always keep the last release updated for a year or so.

https://wiki.debian.org/DebianReleases