Save your money for literally anything else.
One of the biggest selling points for me was the zombies, but zombies is terrible! Literally DMZ but with zombies and some mercenaries. You loot, kill zombies, do some missions for perks and exfil with your loot. Sounds great on paper, but you'll grow tired within a few hours. Zombies has strayed far from its roots. It's such a shame in the current state.
Multiplayer is a joke. To give credit where credit is due, the movement feels more fluid. But it still feels like a really cheap game. I feel Battlefield 2042 has better multiplayer, which I wasn't a big fan of. I didn't play the MW3 beta, but if I did, I would've requested a refund. The perks are gear which is a neat concept, and they added some new lethals, tacticals and kills streaks. But something about it doesn't feel right.
The campaign is terrible, the cut scenes where the only good thing about it because you weren't playing the campaign. The campaign is extremly short and glitchy. The open levels are a lot like the Battlefield campaigns.
As everyone is saying, it's a $70 DLC. You're better off finding a new hobby until they can fix the current state this game is in. If you still want to buy the game I'd recommend watching some reviews on YouTube before you do and send those guys $70 for saving your time