Aside from a minor tease on their Twitter from a year ago, TellTale hasn't actually confirmed that there will be a follow-up. While the game sold well enough, it has been significantly oversold by The Walking Dead and Game of Thrones. TellTale has said that a third season of TWD is in development as well as a second season of GoT. On top of this, they have hinted at a "mystery project" based on a popular franchise that is in the concept stages as well. This means that their 2017 schedule is pretty much set.
So, while they haven't said there won't be a second season of The Wolf Among Us, they also haven't said that there will be one. Having said that, the game definitely has passionate fans and was even popular enough to receive an official comic book adaptation. Considering that the Fables comic has now ended, a second season of the game would allow DC/Vertigo to produce another miniseries, so I'm sure they would approve it. We just have to wait and hope that something materializes over the coming year.
TL;DR - No news about season 2...yet.