The surprise of the season so far has been the 3-0 Buffalo Bills who have not made the playoffs since the 1999 season. This is a team that people expect to lose a lot of games. Instead, the Bills are one of only three teams in the league with an undefeated record.
There are two ways to look at this. According to Stats LLC, there are only six teams in the history of the league that have won twice in the same season in games they trailed by 18 points or more. The Bills have done that in back-to-back weeks.