As for the game’s plot, it’s set 23 years after the events of the original Alien trilogy. You play a Colonial Marine onboard the USS Endeavor, mowing down as many Xenomorphs as you can. There are also five classes to choose from, according to the Aliens: Fireteam Steam page.
Aliens: Fireteam even has a trailer on YouTube, which is embedded above. Though it does note that the footage you see is of gameplay during the alpha stage.
That being said, the game is coming along pretty well, with a release date scheduled for some time in summer 2021. In addition to the aforementioned Steam, the game will also be available on current and previous generation Xbox and PlayStation platforms.