Now that the Night King is dead, the rest of Game of Thrones season 8 will be about finishing the last war, with Cersei being the final villain. Ever since Robert Baratheon was killed in Game of Thrones season 1, the series, not to mention George R.R. Martin's A Song of Ice and Fire books, has been about defeating the Lannisters and taking the Iron Throne. The War of the Five Kings started shortly after Robert's death, but it's since dwindled down to just two monarchs: Cersei and Daenerys Targaryen.
Of course, the battle for the Iron Throne took a backseat while Daenerys pledged her army to Jon Snow's cause, to defeat the Night King and win The Great War, thereby saving all of humanity in the process. But now that The Great War has been won - thanks in large part to Arya killing the Night King - the next step is ultimately taking the Iron Throne away from Cersei, who recently paid a large sum of gold to the Iron Bank in order to recruit the Golden Company to her cause.
While Cersei didn't get the elephants she wanted, she did get enough soldiers with the Golden Company, and currently has the Iron Fleet at her side as well as the entire Lannister army. So, she has a big enough army to stand against Daenerys Targaryen and her army, though it remains to be seen just how many people survived fighting the Army of the Dead. While it was believed Daenerys could ultimately became Game of Thrones' final villain, primarily because of Jon Snow being Aegon Targaryen, it appears that they've united in their fight against Cersei.
Jon Snow's lineage - his mother being Lyanna Stark and his father being Rhaegar Targaryen - makes him the rightful ruler of the Seven Kingdoms. But given that he's never wanted to be king - and arguably his true purpose in Game of Thrones, which was to kill the Night King and destroy the Army of the Dead, is finally complete - he may not want to assume his position as the last Targaryen heir and instead remain a Stark.
Regardless of what happens, Cersei is the last true threat in Westeros. She's somewhat become a mad queen, and her willingness to kill anything and everyone - including her own brothers - means that many people will ultimately side with Daenerys, especially once word spreads about the Battle of Winterfell. But who gets to kill Cersei, if she even loses, remains to be seen. It could be Daenerys or Arya, or even Jaime - but audiences don't have to wait long to find out as Game of Thrones' final season is already halfway done.
Game of Thrones season 8 continues on Sunday, May 5, on HBO.