It might be the end of Grey's Anatomy, at least that's what series show runner Krista Vernoff implied in an interview The Hollywood Reporter.
Vernoff said as the end of Season 17 approaches she is planning for two alternate endings," I'm planning a season and a finale that could function as either a season finale or series finale. I'm planning for both contingencies and it's hard and it's not ideal. It's not where I wish we were."
ABC has yet to reach a new deal for the series 18th season, but if it is the end Vernoff says "there will be closure."