If Leverkusen extends the contract of Xabi Alonso they will not let any other teams including Liverpool or Bayern Munich even think about their coach to hire Xabi Alonso for the next season. But the fact about Xabi Alonso and Leverkusen is they are going to play in the Champions League for the next season and if they have Xabi Alonso, they will be a strong team in this tournament. However, I think Leverkusen will also need to hire some players and get improve to make them ready to play against stronger teams like Real Madrid.
Sadly we don't have Leverkusen in the Champions League in this season, but I'm waiting for it until the next season.
Elite teams will fight to reach the tournament, I'm talking about the club's that failed to qualify this season. The UEFA Champions League title should probably be the next target for Xabi Alonso because he showed too much competent actions and capabilities of lifting the club to next phase. Bayer Leverkusen board, players and the supporters are happy to have a coach like Xabi Alonso who's very busy with the game spot. Xabi Alonso is not leaving Bayer Leverkusen this season, they're more dependent on the coach who's consistent in streak winnings.