If they managed to do it being set in WWII without a doubt they'd beat COD. I've never been the biggest fan of Battlefield but from what I saw with Hardline if they can top that off with the new release expected to be in WWII I would more then definitely buy it.
Battlefield 5 was indeed based on WW2 and released on the 15th of November. It hasn't beat out COD and probably won't since it actually lost a huge chunk of revenue because of how it portrayed itself during the reveal trailer. (Historically inaccurate with half robotic girls lol). Oh and it jumped on the Battle Royale wagon