Brienne hasn't had much to do this season, but when word of Jaime's death reaches her, she will no doubt take action. No, she won't go on a vengeance mission to take down Daenerys — she understands the costs of war. But she will no longer be content with sitting on the sidelines. Jaime gives her Oathkeeper because he believes in her, and the best way for Brienne to honor his memory is for her to fight as valiantly as Jaime did. Whether that means fighting White Walkers in the North or Cersei in the South remains to be seen, but you can bet Jaime's death will be a turning point for Brienne.
While Jaime's fate remains uncertain, there's no doubt that his death could upset the power balance in Westeros in unexpected ways and leave the people who loved him grappling with what they should do in the aftermath of their loss.
