Deadpool broke every box-office record an R-rated movie can break, and even boasted the biggest opening weekend of any of 20th Century Fox's X-Men movies (regardless of rating). So the fact that Deadpool 2 is confirmed (with the same creative team of director Tim Miller along with writers Rhett Reese and Paul Wernick) should come as absolutely no surprise.
Hard news has been a little scarce on the Deadpool 2 front, though, which is understandable. After all, it only just came out in February, and 20th Century Fox had to get their PR machine together for X-Men: Apocalypse in May. And while we still don't have an official release date (although, see down below for some educated speculation on that), things are coming into focus about when Deadpool 2 could arrive, or at least when it will go before the cameras.
Collider caught up with Simon Kinberg who confirmed that "[original Deadpool screenwriters] Wernick and Rheese are working on the script and we hope to have a script very soon." As for when it might go before the cameras, that's a little more vague, but he does say that they "hope to shoot the movie around the beginning of next year."
20th Century Fox has two dates on its 2018 calendar reserved for Marvel/X-Men related properties: March 2nd and June 29th. If Deadpool 2 does indeed go into production in early 2017, then one of those is certainly possible. I'd lean towards the March date since it's fairly close to where the first film opened (which was in February), but obviously this can all change at the drop of a hat.