Bayer Leverkusen started this year great. In the past, Dortmund was in the league title race with Bayern Munich. This year, it seems that Leverkusen will also take part in this race. Bayern Munich has become much stronger with Kane. Now I think we will see players fighting to win every match in the league to help Kane win the championship. There will be a tight race between Leverkusen, Bayern and Dortmund.
Leverkusen and Dortmund are really going to be a hitch in the way for Munich as they are both not relenting with efforts to be at the top of the League and possibly win the league title, but then Bayern Munich isn't sleeping on it although they may not be leading on the table at the moment but I'm sure they still have enough time to build on their strength and get to the top.
The season hasn't gone half way so there is still a lot of time for them, Kane will definitely influence Munich strength to further make progress with subsequent matches. Leverkusen's strength now is stronger as Xabi is stoping at nothing to make sure he becomes the champion of this league this season, although Bayern have had similar experience as this where they dropped in their strength and later won the league.
Dortmund may only try to be a contender but I doubt they would have what it takes to be the champions they will only finish tops and qualify for UCL and for the bundesliga next season, but then it's too early to start predicting possible winner of the league so let's still keep an open mind as anything can still happen by the middle of the season.