Call of Duty Warzone is a free to play battle royale version. The game can support upto 150 players on a single session. The game will also have Drop in, armor up, loot for rewards as mentioned on the website.
We also found a worldwide relase map shared by Activision on the exact release dates of Warzone based on your location.
The game is being released on PC and PS4. Have you tried it out yet?