Chun-Li is an international Cop from China whose job is to rid the world of M.Bison's Shadowloo Organization. Originally appearing in Street Fighter 2 in arcades and consoles, she rose to popularity with Evo Moment 37 when Diago Umehara beat Justin Wong in one of the most ridiculous come backs of our generation. Though she was on the opposite end of that beat down, she maintained her presence in virtually every fighting game made by Capcom but this is her first appearance in a MvC game since the original.
In a nutshell
Though she sports a fireball that can cause a crumple, she excels as a rush down character. Having a quick OTG allows her to convert awkward combos off any situation and having one of the easier TAC infinites in the game means she can make the best of bad situations. She only has a one way dash but it's enough to provide airborne pressure and give her high/lows. Probably the biggest barriers to playing this character is that she's a charge character with an execution barrier and limited damage potential.
Activating a spinning bird kick very close to the ground makes for a very fast overhead that recovers very quickly if blocked. If it connects and you correctly timed the input, Chun-Li will recover fast enough to start a ground chain into a combo.
Since Chun-Li's normals are jump cancellable, you can also use this technique to extend combos.