Bayern Munich is also still one game behind Leverkusen so the gap in points seen now is four points, but if Bayern Munich's matches are the same as Leverkusen's number of matches and Munich can win. So the point gap between the two is just one, not four points, unless Munich cannot win in its 16th match in the Bundesliga. Apart from that, Leverkusen this season only competed in the European League apart from the Bundesliga, not in the Champions League like Munich. So the pressure these two teams have is certainly very different even though they often look the same in the Bundesliga.
You're right. Bayern Munich has 1 unplayed match. If they win the unplayed match, their point will be 41, the point gap is 1 point only. So, actually Bayern Munich is still has a big chance to compete for the title this season. However, Bayern Munich must ensure that they won't miss again 3 points for the next matches. If both Bayern Munich and Leverkusen can play consistently in each match, it will be a tough competition for the title this season. And the next match Leverkusen vs Bayern Munich is probably to be a crucial match to determine which team to be the champion in this season.