I think Jinx's chaotic nature would get under Tracer's skin, what with her more heroic nature, especially since they're both kind of light hearted people outside of the more violent parts of their lives. It might be funny to have them be rivals in their more vigilante style activities and then maybe a bit flirty in a kind of "does she like me or is she just like that?" way in their day to day lives, with neither of them making the connection until later.