Woody's Finest Hour

A TV show or another entertainment medium has one episode/serial end with a Cliff Hanger Ending leading up to the next episode, but there's just one little problem with that...

The TV show and/or said entertainment medium ended up cancelled before they resolve the cliffhanger due to varying circumstances.

The Trope Namer came from Toy Story 2.

Films

 * The Trope Namer refers to the Toy Story 2 in-universe children's show Woody's Roundup. The final episode featured Woody and Bullseye attempting to jump the Grand Canyon to rescue their friends the Prospector and Jessie from imminent destruction. The next episode never aired as the show was cancelled due to the launch of Sputnik.
 * An In-Universe example is found in Galaxy Quest; the original TV show the actors were in was cancelled, but the final episode ended with the words "Activate the Omega 13.". Fans had spent years trying to figure out what the Omega 13 might do, since there were no further episodes to show its use or effects.

Live Action Television

 * The Sarah Connor Chronicles ends abruptly due to this shortly after Angsty Teen!John Conner gets himself sent to a future where no one recognizes his name due to being pulled out of the timeline.

Web Original

 * Not quite an episode itself, but Smash Kingdom had the Sonic vs Mario clip, which ended with a cliffhanger as Super Sonic and Super Mario resuming their fight. However, it was not resolved in the last episode of the series.
 * Super Mario Bros Z had something similar happen: The episode sets up a cliffhanger for Episode 9 regarding Basilisx fighting Mario and Mario being at his mercy due to being poisoned. Unfortunately, thanks to a lack of motivation on Alvin Earthworm's part, the series got cancelled before Episode 9 got released.
 * Episode 9's first scene did get released, though. Unfortunately, it leaves it on a bigger cliffhanger with Mario and Luigi squaring down with Basilisx and Shadow with Mecha Sonic... On the other hand, the ending of the trailer, as posted on Alvin Earthworm's Deviant ART account, does have the words "The End?", implying the possibility that he might consider restarting the series at a later date.

Web Comic

 * RPG World made it all the way up to the final battle before the Creator Breakdown the author had over people wanting him to finish the story before moving on to side projects finally made him give up on the whole thing.
 * It seems traditional for A Modest Destiny to be cancelled just as some sort of epic climax is about to occur (or, is in fact, occurring), only to be once again resurrected. Only to be cancelled again. Then resurrected. Then cancelled. There's a pattern here, is what we're saying.

Western Animation

 * The last episode of Xiaolin Showdown ends with all the villains gathering together for a last Xiaolin versus Heylin Cosmic Clash Showdown.
 * The show Sonic Sat AM had a very resolving ending...until the last 10 seconds, where they pull a cliff hanger on the audience. The show was promptly cancelled after that.
 * The last episode of Exo Squad ends with JT Marsh watching in horror as strange alien ships appear out of nowhere, steal Mars (yes, the whole planet), and disappear again.
 * Sym-Bionic Titan. The conflict was building up, the show was gaining fans, and the staff was all set to make a second season. Then the show got canceled because it failed to secure any key toy deals. Attempts to get the second season made were fruitless, and Genndy Tartakovsky was so displeased with the way Cartoon Network handled his series that he left them to form his own studio under Sony.