Call of Duty has used the (typically $50) "season pass" concept for ages, and despite mixing it up a bit last year, they're completely overhauling the concept for 2019's Modern Warfare. We already knew they were doing this to an extent to not "split up the userbase" now that full cross-play is happening (read: PC, PS4 and Xbox One can all play together), but today they explained what that actually means. The short of it? Modern Warfare will make its money (beyond the $60 entry fee) with battle/season passes.
That's a fine way to to do it. Not as generous as making it all free, not as greedy as charging for a $50 season pass for content on top of loot box support. Pretty much every other major game (Fortnite, Dauntless, Apex Legends, Rocket League, Magic: Arena, the list goes on) is doing the "battle/season pass" setup, as it's a fairly lucrative way to get people to pay out and keep them in the ecosystem as long as possible.
Activision claims that it's specifically not doing a "loot box system" (will they eat those words in six months?), and "all functional content that has an impact on game balance" (non-cosmetic) can be earned by playing the game. The battle pass system is going to be transparent, like the others, so you can see what you're eventually unlocking as you level up. Again, the goal (the initial, right-now idea) is that all premium stuff is non-cosmetic "and does not impact game balance."
The publisher says the first pass will not arrive on October 25 when the game launches (as is customary, for "pre-seasons" to kick off) but sometime "later this year." You good? Allegedly you can just play the game and unlock everything, and enjoy free content drops with cross-play. On paper that's not a horrible deal, but Activision has made those deals worse all the time after launch: let's see if they stick to this missive.
Post-launch approach to new content [Activision]