This is the trailer for Final Fantasy VII Remake, which, as its name suggests, is a remake of the classic (and revered) RPG, Final Fantasy VII.
Final Fantasy VII Remake is designed mainly to appeal to people who loved the original, so Square Enix is assuming everyone already knows the story.
With that in mind, if you have never played Final Fantasy VII, you should avoid watching this trailer for the remake, as it contains spoilers.
Everyone else can enjoy glimpses of the story, battle system, and cutscenes. And, for the first time, we get to see Cloud Strife wearing a dress, as well as Red XIII.