In the leadup to its announcement, it was heavily suggested Call of Duty: Modern Warfare 3 would be a huge expansion for Modern Warfare 2. That didn't turn out to be the case as Activision is selling the FPS as its own standalone PS5, PS4 title, but there is one situation where the game quite literally is a DLC add-on: its Trophies. It's been spotted by Powerpyx that the Modern Warfare 3 Trophy list doesn't get its own listing on your PS5 Profile; rather, it's been categorised as DLC for Modern Warfare 2.
The PS4 version of Modern Warfare 3 does have its own listing and a Platinum Trophy to earn, but the PS5 version lives under Modern Warfare 2, and therefore requires you to own and finish a completely different game if you want to obtain 100 per cent completion on your PS5 Profile. As well as reaching level 55 in multiplayer, you will need to complete a few challenges in the new open world Zombies mode and perform specific feats in single player missions.
It's pretty unprecedented for a AAA $70 game of this nature to ship without a Platinum Trophy, with only a select couple of indie titles making it to market without the coveted gong. One reason this has happened may relate to the way Call of Duty games are accessed via the Call of Duty HQ app. For a few years now, the likes of Warzone 2, Modern Warfare 2, Vanguard, and Black Ops Cold War have all fallen under the same launcher, meaning you can switch between them all from a single menu.
In practice, this is more of a hassle than it needs to be, but it's designed to create one cohesive destination for all things Call of Duty. This single hub may now be replicated in the Trophy listings, and Modern Warfare 2 has been chosen as the lead name for what everything henceforth falls under. The thing is, though, collections of multiple games have been getting around this issue for years now.
The Mass Effect Legendary Edition was able to be broken off into individual Trophy lists for each of the three games, and while the recent Metal Gear Solid: Master Collection handled it very clumsily, it too gave each PS1 and PS3 title a Platinum Trophy separately. There is a way around this problem, but it appears Activision hasn't utilised it. If you really do need the Platinum Trophy in Modern Warfare 3 — named A Soldier's Purpose — it's the PS4 version for you.