Even though they managed to end the season as an undefeated team in the Bundesliga, Leverkusen is not yet experienced enough in the Champions League, they must be prepared tactically and mentally to face strong teams such as Real Madrid, Manchester City, Inter Milan and PSG. Xabi Alonso must be able to maintain the quality of his team to face next season which is full of challenges, perhaps signing several quality players is needed to add depth to his squad. Leverkusen could make a surprise in the Champions League like Dortmund did this season, but to become champions in this competition requires high concentration and maintaining consistent performance.
Leverkusen this season has made history by winning the Bundesliga title for the first time in the club's 120-year history, the history is even more impressive after they were able to achieve it with a record of 0 defeats in the league, next season of course Leverkusen will try to continue their positive trend by playing in the Champions League, so indeed Alonso needs careful preparation to be able to repeat and also maintain their performance next season both in the Bundesliga and Champions League, looking at the list of teams that will play in the Champions League next season, of course Leverkusen should start trying to improve their current squad.
Alonso is one of the smart coaches who is able to make a lot of changes to Leverkusen, so indeed the fans and management of course have high expectations for Alonso to be able to bring glory in the Champions League next season, but I think the management should also try to keep each of their star players so that they are not taken by other teams, so far it is reported that Leverkusen has lost some of their players who have indeed been recruited by other teams, So it will likely be difficult for Alonso to maintain Leverkusen form next season if they continue to lose their players.