Thanos don't want no problems.
The Captain Marvel trailer touched down during Monday Night Football this week, and Brie Larson's hero put her powers on full display. Captain Marvel will be the most powerful hero in the Avengers, when she joins, and it should be fairly easy for her to defeat Thanos. Unless the Mad Titan utilizes all of the Infinity Stones to mercilessly destroy time and space as we know it, he doesn't stand a chance against the overpowered hero. Captain Marvel will undoubtedly take the place of Captain America in the MCU as the leader after he leaves. Their parallels are too obvious to ignore. Both were displaced from their average lives, both joined the military, both become superheroes, and both have complex relationships with their close friends (Bucky Barnes/ Yon-Rogg). Marvel fans took to Twitter after the trailer dropped, and crafted hilarious memes showing Thanos' reaction to seeing Captain Marvel.
Thanos may have a hard time battling Captain Marvel, but I have a sneaking suspicious Marvel is gearing up to launch their next string of baddies: the Skrulls. The Skrulls will appear in Captain Marvel as the shapeshifting aliens that are trying to take control of the galaxy. They may also appear in Avengers 4, since early synopsis' for the film hint at a new bigger threat. Only time will tell, but setting up the Secret Invasion storyline for phase four and beyond looks like the path Marvel will be taking.