This indie PC shooter is called Signal Ops. If you've ever played, say, Space Hulk, it may look slightly familiar, with the same mechanic of giving you control over four people at once. Only, it looks way more complex.
While it obviously owes a lot visually to Team Fortress 2, notice what happens at the start. You, the player, walks up to a screen in first-person view, and are then able to control other people from a first-person perspective. We're standing on the brink of a bottomless rabbit hole here, people.
The developers, Space Bullet, say that its combination of stealth and team play "draws inspiration from classic games such as Commandos, Syndicate, and Deus Ex", which if you're a PC gamer is one hell of a checklist to start ticking off.