Today would've marked the finale of BlizzCon 2020, and while the convention's cancelled for obvious reasons, Blizzard has confirmed that we're getting an online replacement for early next year. Today, president J Allen Brack hosted a 'fireside chat' addressing the current state of the company's games, and confirmed that the digital BlizzCon will be free.
"We want it to be a big, virtual celebration," Brack says, "so BlizzConline will be free to watch and engage in." The BlizzCon 2021 dates are set for February 19 and 20 – I don't think anyone's actually calling it 'BlizzConline' out there and as Brack notes, February will coincide with Blizzard's 30th anniversary.
Blizzard still hasn't confirmed what we'll be seeing at the online event, beyond a number of community-focused things like cosplay showcases. In the video, Brack briefly touches on games like Overwatch 2 and Diablo 4, but doesn't confirm whether we'll be seeing those titles at BlizzCon. But Brack does add that "it's safe to assume that we're exploring other things farther out on PC, console, and mobile, as well."
Mostly, the video runs down major recent and Blizzard releases, like the incoming multiplayer games.

The Diablo 4 release date are both still up in the air, but fingers crossed that we'll know more soon.