Alonso leaving Bayern Leverkusen will really really affect them at the same time I'm thinking it's because he left the club that's why some players too left the club to other clubs. Alonso really brought out the best out of this Leverkusen team. Ten Hang has a mountain to climb because the fans will be expecting a lot from him when the season starts.
Xabi Alonso's departure was a heavy blow for Leverkusen fans, as they had grown to love the manager for his results over the past two seasons.
After he left, several promising players who contributed to Leverkusen's success last season also left, so I believe Leverkusen's performance isn't as strong as before, and Ten Hag has a tough job to do to restore Leverkusen to its former glory. Naturally, fans are enthusiastic about Ten Hag results, and Leverkusen's management has entrusted him with the job.