Jeff Kaplan confirmed that Overwatch team will never introduce jetpack cat.
But what about a catgirl? Genetic engineering is advanced in Overwatch universe, so it perfectly fits in tone of the game.
I even made a backstory for her. She ran from her owner and started to live in the streets, but luckily, agency picked her up and she became a pop-star promoting a support of animal rights. Until something horrible happened.
Her haters drugged her, so she would show her predator nature. Her career was ruined because she killed a bunch of people while drugged, and she came back to the streets to punish injustice.