2. The Divergent Series: Ascendant
The Movie: As so many young adult movie adaptations tend to these days, the final book in the Divergent series was to be split into two movies, Allegiant and Ascendant, the latter of which was intended to be released in 2017.
Why It Got Cancelled: After Allegiant grossed over $100 million less than either of its predecessors, plans for Ascendant were quickly put on hold.
Word spread that the project would be made as a TV film instead, which caused numerous cast members, including lead Shailene Woodley, to pull out, effectively killing it dead.
At present, a TV series based on this universe is in development, but the movie series popped out of existence without anything approaching a resolution, which sucks for the fans, as terrible as these movies were.
At least it means Shailene Woodley got a juicy role in Big Little Lies instead, so it all worked out for her in the end.