This is partly "remembering bits of a dream I had" and "doing post-dream design refinements to the concept":
A first-person shooter of some variety (the dream version was a mix of TF2 and
Ravenfield) where the main gimmick is that each players gets to place four or so teleport spots that they can teleport to at any time, with the caveat that it takes a few seconds to do so, and one is vulnerable while doing it (so it's not instant). At least within the dream (I think), two of the spots started off at your team's two distinct spawn points, so you can warp between them.
The teleport exit spots would be visible by enemies and could also be destroyed, to prevent spawn-camping and other such tactics.
I'm not really sure on the gameplay specifics of the game beyond this main teleport thing, but it would definitely be something that can play well with it - so basically, not "capture the flag", at least not without some twists to it, like being unable to teleport while carrying the flag.
I also like to imagine that one would have the ability to change the behavior of their teleporters, at the cost of having access to fewer of them - say, you only get 2 or 3 teleporters, but you get a brief speed boost after teleporting. Or they go invisible after a while. Something like that, in addition to the more conventional weapon/loadout/class customization that would inevitable also be a part of this.