Activision has detailed Call of Duty: Vanguard's first season pass, and the big news is what it calls 'killcam vanities'. Killcams in the context of Call of Duty play briefly after you've been killed, showing how it happened, and at the end of every game all players will see the 'best' multikill of the match replayed—so you can see why players might desire killcam cosmetics.
These are borders that go around killcam replays and, well, they sure do look like Call of Duty cosmetics. The one below is called Scrapyard, and looks a bit like the logo Bret 'Hitman' Hart wore. Not enough pink though.
Needless to say there's an absolute boatload of weapons, skins and so on across the free and premium battle pass tracks, all of which are detailed on the official site. The more noteworthy additions are three new operators and five new weapons for Warzone, alongside the new Caldera map of course, and two maps for Vanguard: Paradise and Radar, the latter a version of Dome from World at War.
The killcam cosmetics jump out simply because I'm not sure I've seen them monetised in this way before (you have to buy the premium pass for $10 then grind them out). Lots of games have included things like death effects that change how targets die (Valorant a good recent example), and games like Counter-Strike: Global Offensive allow you to set a little jingle for the end of rounds you get MVP in. Having Death in the corner of a COD killcam is actually quite cute: I'll take it!
Here's the video announcing all the shizzle.
But yeah, as these things go, killcams make some sense as a customisation option. Let's be frank, Call of Duty has the problem every live service game has: producing endless new content that can be used to fill battle pass tiers and challenges across both free and paying players.
Anything that can fit into this churn is fair game, and cosmetic killcams fit the bill of having a noticeable in-game effect, and each one can probably be turned into a dozen or more 'variants' over time with minor fiddling. That Bret Hart one could be back next season with a nice gold tint. Maybe we'll get Death with red glowing eyes. Don't bet against it.