In the Game of Thrones series finale, a council is held where
the North asks for and receives its independence.
Another question touched on the subject of why the Iron Islands didn't ask for independence as well, and the consensus there seems to be that Yara didn't have the political savvy or the clout to pull that off.
However, could an alternative interpretation be that the question of the Iron Islands' independence was already settled, because Daenerys promised it to Yara in Season 6, Episode 9, and this promise was honoured?