Contains major spoilers for ALL of Game of Thrones.
After eight years of political maneuvering and backstabbing, sex and violence, t*ts and dragons, Starks and Lannisters, deaths and rebirths, lights and shadows, monsters and men, Game of Thrones is over. Like, for good.
The show came to a close with series finale The Iron Throne, which resolved a number of major character arcs and plot threads. The Iron Throne was destroyed; Daenerys was killed by Jon Snow, who then retook the Black and went beyond the Wall; Sansa was made Queen in the North; Arya sailed to find what's west of Westeros; and Bran became King with Tyrion as his Hand, and a Small Council including Sam, Bronn, Davos, and Brienne.
While it was wrapping all of that up, however, and even characters such as Edmure Tully and Robin Arryn got a last look-in, there was plenty it simply had to leave hanging. Whether it just wasn't important to the main story, they didn't have time, or they kind of forgot about it, there are a number of plots left unresolved by the end of Game of Thrones.