Grindelwald's Plan and the Philosopher's Stone
For the reasons mentioned previously, we probably won't see the Invisibility Cloak or the Resurrection Stone in Fantastic Beasts: The Crimes of Grindelwald. Those two Hallows are both stowed away, waiting for Harry Potter to discover them in about 70 years. However, the movie could instead see Grindelwald chasing a different MacGuffin: the Philosopher's Stone (or, as it was called in the American versions of the Harry Potter books, the Sorcerer's Stone). The major tip-off that the Philosopher's Stone could play a role in Fantastic Beasts 2 is the fact that its creator, Nicolas Flamel, is the movie, played by Brontis Jodorowsky.
The Philosopher's Stone was encountered by Harry Potter in his first year at Hogwarts, as Flamel had handed it over to Dumbledore for safekeeping. The Stone creates the Elixir of Life, which grants immortality - something that naturally drew Voldemort towards it. Because of its association with cheating death, critics of the collection of wizarding fairy stories The Tales of Beedle the Bard have speculated that the eponymous Beedle was inspired by the Philosopher's Stone when he wrote "The Tale of the Three Brothers" - the story that explains how the Deathly Hallows came to be. In short, some in the wizarding world believe the Resurrection Stone and the Philosopher's Stone to be the same object.
It's a reasonable assumption, since the Philosopher's Stone was created by Flamel in the 1300s and the Peverell brothers lived and died in the 1200s, meaning that both stones emerged at approximately the same period in history. If Grindelwald believes that the Philosopher's Stone is the Resurrection Stone, he would probably stop at nothing to possess it, given his obsession with the Deathly Hallows and his lust for power. Since the Philosopher's Stone is in Flamel's possession at the time when Fantastic Beasts 2 takes place (he needs to keep it nearby, so he can have a ready supply of the Elixir of Life), Flamel could end up with a target on his back.
Based on what we've seen of the movie so far in this teaser, it seems like Fantastic Beasts: The Crimes of Grindelwald is interested in revisiting the franchise's roots. It will take audiences back to Hogwarts, and feature Dumbledore as a key character. Given that the Philosopher's Stone and the Resurrection Stone bookended the original run of stories, it would certainly make sense to bring back the former as a pivotal object. Eternal life is a tempting prospect, especially for a wizard like Grindelwald.
If the Philosopher's Stone is the object of pursuit in Fantastic Beasts 2, we know that ultimately it will end up safe and sound in Flamel's possession, just like we know Dumbledore will ultimately defeat Grindelwald in a later sequel. Still, knowing how things end up won't make the journey any less interesting.