This depends on what Xabi Alonso's decision will be, whether he will leave Leverkusen or whether he will prefer to stay. At the moment there are still many who say that Xabi has had great luck this season with Leverkusen, so if he wants to prove that wrong then he would prefer to stay in my opinion, but if he is going to use this opportunity to manage a bigger team in the league who is more competitive, then it is likely that he will leave Leverkusen.
Currently I don't see any signs that Xabi will stay or leave, because it seems he prefers to first focus on Leverkusen to become champions in the Bundesliga, even in the Europa League. He likely realizes that he must complete the tasks he has now before he decides what he will choose for his future. Stay or leave, I'm sure Xabi will consider this as best as possible, because this also concerns his career as a coach, he will consider it carefully before finally making a decision.
One thing that is certain is that Xabi Alonso will leave Leverkusen sooner or later, it is difficult to refuse an offer from a club as big as Bayern Munich or Liverpool. However, for now, Xabi Alonso target at Laverkusen has not been achieved, namely winning the Bundesliga, DFB Pokal and Europa League trophies, so it makes sense why until now we have not heard any official news about his future. When the season ends and the transfer window opens, everything will look real, however, not a few people hope that Xabi Alonso will stay at Leverkusen until his contract ends.
Apart from that, I assume that Xabi Alonso future decisions really depend on how Leverkusen management sets the vision and mission for next season. One of the most influential is retaining their players and recruiting new players to compete in higher competition, namely the Champions League. If the club officials cannot grant this, in my opinion Xabi Alonso has the potential to leave Leverkusen. Before all that happens, we will of course first enjoy how many trophies Leverkusen can win this season.