After the introduction of the Nova Corps in 2014's Guardians of the Galaxy, the introduction of the Nova character was always inevitable. When exactly that introduction will happen remains to be seen, but he would be a very useful ally for the heroes in the Avengers: Infinity War movies.
He is Richard Rider – a New York high school student who was selected to become the new Nova after the last surviving member of the Nova Corps, Rhomann Dey (played by John C. Reilly in Guardians of the Galaxy), passed away. In Guardians of the Galaxy Vol. 2, Thanos is likely to destroy Xandar – home of the Nova Corps – which could result in the same thing happening.
The character would provide a direct link between Earth and the cosmos and his incredible power – which may well come from the Infinity Stone known as the Orb in the MCU – could prove decisive in bringing the Mad Titan down.