X-Men: Apocalypse is set in the year 1983, and the trailer revealed that at least part of the movie is set at the Alkalai Lake facility where Wolverine went through the Weapon X program.
Last month, just after the third trailer debuted, the filmmaker teased that Wolverine has an important role in X-Men: Apocalypse.
Last month, 20th Century Fox debuted the third trailer for X-Men: Apocalypse, which revealed quite the surprise for longtime fans of the franchise.
We also recently reported that the post-credit scene helps set up a number of possible movies within the X-Men franchise.