Canonical is already planning its first Ubuntu distribution next year which will be Ubuntu 22.04. The release date will therefore be the end of April 2022. This version will be an LTS version which means that it will benefit from long-term support lasting at least 5 years.
Ubuntu 22.04 will be the first Ubuntu LTS that will come with the GNOME 40 series desktop environment. GNOME 41 or 42 probably.
It is also likely that Ubuntu 22.04 will ship PHP 8.1 e GCC 11.x