We finally have the longer and more in depth Captain Marvel trailer which explains a lot of things about Brie Larson's take on Carol Danvers A.K.A Captain Marvel. She's originally a human pilot but has been made Kree and is part of an intergalactic group of heroes called StarForce.
Danvers finds her way back to Earth during what seems to be the Skrull-Kree War, an galaxy-wide battle between two warring alien civilizations. We see glimpses of various evolutions of Captain Marvel including the epic Binary persona which can channel the power of a star. How will Captain Marvel lead into Avengers 4? We'll have to wait until March 2019 to find out.