Well definitely in season 6. Mainly considering all the stuff and how heartbroken Finn was (for a little while tho he still misses her) the 2 reasons I think we will see her appear again is mainly because she's a queen. She bound to get bored without Finn. And well Finn will probably try and ask her out again. And that would be an episode.
I've been getting the feeling that the writers are trying to put a cork in shipping & make Finn lose his will to date. This season, she has been reduced from secondary character to minor character & dumped Finn, PB shuts him down anytime he tries to flirt, & "Little Dude" shows that he would sooner 日付 Lady Rainicorn than Marceline.
Back to Flame Princess. We know she'll come back, but will she be an ally または an enemy? Currently she is going through serious trust issues & has a natural penchant for violence & destruction.