The greatest factor in getting COD: Warzone that much players in such a short amount of time is the Genre of the game. There are a lot of traditional FPS games out there. These include CS:GO, the upcoming valorant and more. These games start feeling repetetive once you've played them for a while and since there's nothing much different in them, it starts getting old and that's when players move to other games.
COD: Warzone could have followed the same approach but instead they decided to go for this Open-world action filled Battle royale. It's gameplay is much more forgiving, if you die, you have many chances of respawning back in the same game and getting your revenge. There are Helicopters, lots of vehicles and more.
Overall, it's like a combination of Battlefield open world action with PUBG's Battle Royale Genre that's both forgiving & awesome to play.
Gaming has seen a massive surge as people stay home during the lockdown. These times might be difficult but gaming has helped ease the tension at a massive scale and that's another factor that boosted popularity of COD: Warzone.
Consistent Bug-Fixes & Patches
COD: Warzone has had problems but since nothing is perfect, it's forgiveable. The developers did a very fantastic job of patching the in-game issues. All the updates are tested before they reach general audience. That way, the player base stays happy and a happy player base is what keeps a game alive and growing.
Final Fantasy VIII is a love story with some mental apocalypse happening in the background. It is often considered by some to be the black sheep of the Final Fantasy series, and disappointed many fans, including myself.