Maybe none could expect to see this good performance from Leverkusen during this season. While a team like Bayern Munich spends too much money and they hired players like Harry Kane for their team to have better performance during this season in both the Bundesliga and the Champions League but it was not working.
Leverkusen is still unbeaten while they didn't buy expensive players like the other teams and compared to Bayern Munich they didn't invest too much for their team while instead of paying too much money they had a coach like Xabi Alonso in this team who had perfect performance made Leverkusen to have perfect teamwork.
Bayer also has very good players, having only a good coach cannot make a team an invincible champion. It is likely that Alonso is a very good coach if he was able to achieve such a result. He faces an equally difficult task to prove that this success was not accidental, and repeat it again. But we don't know how strong Bayern can be after the off-season, who their coach will be, and what transfers they will make to strengthen the team.