He hasn't been confirmed in or out, but im pretty sure hes not coming back.

Even if he is not a returning character storywise...it seems there is a rumor of all MKDA characters being playable, even if only as Hidden characters and not being part of the storyline. So if Cage isn't a returning character story wise there is a change you can still us him. However, he might not have a story or ending.

I hope that Johnny Cage has some meaning in Deception if he returns. I think Nightwolf has taken his place among the roster.

If Johnny Cage does return among the roster than I hope the developers use Queve's idea for his storyline.