It's very true the fixture between Bayer Leverkusen and Bayern Munich will be a determinant as to who's going bro be very probable to win the bundesliga this season because currently Leverkusen is just few points away from Munich and a win from Munich will means Munich staying ahead of Leverkusen by a point and maintaining such record could get them the trophy.
Leverkusen getting a draw by the end of this game will mean them staying just two points ahead of Munich and that's still a Shakey position which can at any point be taken away from them, Leverkusen has got the home advantage in this game but then Munich still doesn't look like that will be a problem to them but something they will be able to manage by the end of the day, Leverkusen winning will means staying five points ahead of Munich which I think will be the biggest advantage to be sure of winning the trophy because it will take Bayern to win two matches while Leverkusen loose two matches at a stretch aswell which is very likely not to happen.
This match will be the most anticipated event in the Bundesliga this week, but it may be an overstatement that it will be the decisive one of the season. There are still a lot of matches left until the end and during this time anything can happen, injuries, recessions and anything else that can affect the position of the teams in the table. This match is of course very important, there is no denying it, but even if Bayern loses (which I doubt), they will have a chance to turn things around.