Being well past the various freezes, today's GNOME 3.20 release candidate doesn't offer much more than bug fixes and translation updates. If you aren't familiar with the new work added earlier in the GNOME 3.19 development cycle for GNOME 3.20, see our many GNOME 3.20 articles. There is much-improved support for native Wayland on GNOME, many improvements to GNOME's many applications, and other enhancements throughout the stack.
The GNOME 3.20 release candidate announcement issued this morning by Frederic Peters can be read on the GNOME devel-announce-list. GNOME 3.20 will be officially released next week.