Blizzard has confirmed that some of the Shadowlands release date occurs.
Posting in the Battle of Azeroth expansion will remain open for players after Shadowlands is rolled out. "Yes, you will still be able to play through Horrific Visions once Shadowlands goes live," Malin posts in response to on equery, replaying to another: "You'll be able to Island Expeditions and Warfronts, even after Shadowlands goes live."
WoW patch 8.3. They're alternate reality missions showing Azeroth if N'zoth had won, redecorating everywhere as appropriate, and can be done solo or with groups of up to five. Island Expeditions and Warfronts came in with Battle of Azeroth – the former are small 3v3 competitive quests to gather the most amount of Azerite, while the latter are bigger team skirmishes between Alliance and Horde, once side defending an area from hostile takeover.
Players have been exploring the WoW: Shadowlands beta, which is currently underway, and some interesting tidbits have been uncovered, including a Xbox Adaptive Controller functionality to the lands of Azeroth.
We don't yet have a definitive release date for Shadlowlands, but you can best WoW addons if you're looking for more ways to shake-up your fantasy role-playing.