UPDATE 23/07/2020: Another day, another Call of Duty: Warzone season five teaser sent to an influencer. This time it's FPS streamer JackFrags, who received a big Rook in the post from Activision.
Inside the package is an in-universe note from Shadow Company, confirming the Modern Warfare 2 faction will make an appearance in Warzone's fifth season. Remember General Shepherd? It was his lot.
Anyway, from the sounds of things, Shadow Company are called in to sort out the mess in Verdansk, which players are speculating will be rocked by nuclear blasts of some kind. We already know a train is set to run around the map with season five, and the stadium will open up.
Onto JackFrag's video, we see what looks like a tunnel leading into the open stadium.
UPDATE 22/07/2020: A new Call of Duty: Warzone season five tease appears to show the inside of the currently closed off stadium.
Call of Duty competitive streamer Tyler Polchow received a package from Activision with a video he ran during a stream on Twitch.
The video appears to show the interior of the stadium, which is then rocked by an explosion. A nuclear explosion, perhaps? Fans believe it could be a nuke, given nukes have been found in Warzone's mysterious bunkers.
What's gonna happen in season 5!? pic.twitter.com/FodsPkOymv— Tyler Polchow (@TylerTeeP) July 21, 2020
It looks like Activision will continue to tease season five's upcoming map changes via Call of Duty streamers. Expect more snippets soon in the run up to season five's 5th August launch.
ORIGINAL STORY 21/07/2020: A train will hit Warzone, Activision has teased.
Confirming a report from VGC earlier this month, FaZe Clan streamer Nick "NICKMERCS" Kolcheff took to Twitch to reveal a teaser video sent to him by Activision that shows a train in Verdansk, Warzone's map.
This video also includes the date 5th August, which is the expected launch of Call of Duty: Modern Warfare and Warzone season five.
Call of Duty dataminers unearthed reference to an underground train with the release of season four. Warzone "intel" has also pointed to the arrival of a train. The stadium is expected to open, too.
It's expected Activision will continue to tease this year's Call of Duty game, dubbed Black Ops Cold War, in Warzone with the launch of season five. The video was sent to Kolcheff on a USB drive housed in a giant Rook chess piece. The Rook is in the logo of Shadow Company, the enemy faction from Modern Warfare 2, so perhaps we'll see it appear in-game in some description.