It's difficult for Leverkusen because in the end there are only 2 options for the Bundesliga when it comes to trophies, one is Bayern and the other is hoping Bayern play very badly and other clubs can compete for the championship but for this season I doubt Bayern will play badly (like last season).
Bayer Leverkusen made a great start to the league. Their only point loss was a draw against Bayern Munich. Since that game was away, it can still be considered a great success. Boniface, who scored 7 goals in the league, along with Hofmann, Frimpong, Wirtz and Adli are terrorizing all teams. When you play so effectively on offense, things are easier.
Xabi Alonso wants to prove himself as a young coach and has made a very good start to his managerial career. Such young managers usually have a positive impact on teams. Bayer Leverkusen showed that they made the right choice.
I don't know how long they will stay at the top of the league, but they have already shown that they are a serious threat to Bayern München. This season the league looks like it will be more competitive and exciting.