Jubilee will be the next 4* character released and she’ll be the reward in the upcoming X-Men Vs Apocalypse alliance event. She’s an interesting mix of passive match damage increase, stuns, tile alteration, enemy damage and charged tile creation. She appears to be mostly a support character that could probably plug herself into a variety of teams given the universal use for her purple (althought it is expensive) and utility of her passive yellow.
Her S.H.I.E.L.D. Training is currently running with the essentials being Mockingbird, Totally Awesome Hulk and Iceman so give her a whirl!