Speculation about Alonso continues to circulate at the moment and will even peak when it is approaching the end of the season later, so far Leverkusen through his representatives have stated that they will try to keep Alonso in the team next season, and this indicates if there is indeed a desire from Alonso to leave for another team even though he has not confirmed it to the media, I personally am no different than you expecting Alonso to stay at Leverkusen and continue to create records for Leverkusen next season, especially when will they play in the Champions League.
Actually, Xabi Alonso's contract at Leverkusen still runs until 2026, right? However, because of his brilliance in bringing Leverkusen this far, there are several rumors that he is being looked at by several big clubs in other leagues. And especially when Real Madrid almost lost Ancelotti, there were even serious discussions. However, it failed because Ancelotti still stayed at Real Madrid.
And this time, it seems, Leverkusen is quite confident that Alonso will stay at Leverkusen next season. Because the struggle is still quite long, especially next season, Alonso and the squad will face a match that will certainly be very challenging in the UCL. So, if Xabi leaves Leverkusen, I don't know what will happen to Leverkusen's future performance in the UCL. But it does look like he will stay at Leverkusne next season.
In fact, Leverkusen said this:
“He has a contract until 2026 and we are planning the next season with him at full speed. Nothing makes us think that he will not continue with us,” he told Marca.
https://www.thisisanfield.com/2024/03/leverkusen-ceo-insists-nothing-makes-us-think-xabi-alonso-will-leave/