Call of Duty: Warzone will be a free-to-play/standalone battle royale game. According to the details on the game posted on Reddit, it is free-to-play, no Modern Warfare required, but there is cross-play and saved progression. The map of Warzone is massive, and it contains old Call of Duty maps such as Terminal, Scrapyard, Overgrown, Broadcast, and some new areas. There are snowy areas also. 

Warzone will support up to 150 players, with solo play as well as teams of two and three. There are two game modes – a traditional battle royale mode called Warzone and a version with respawns called Plunder. The vehicles include ATV, SUV, Heli, cargo truck, and Tac rover. Warzone will be using the same jumpmaster feature introduced in Apex Legends, allowing one player on a team to decide where the team should drop on the map.

Advertisements of the game have started to show up on Twitch, which means it could probably be available very soon.

Warzone Twitch Ad.

Warzone Twitch Ad.

Edit: Call of Duty: Warzone trailer and download size.

For Modern Warfare owners, the download size 15-22GB and for the new players 80-100GB.