SPOILER: There is a scene at the end of the closing credits: a mutant stands in front of a crowd chanting his name, as he telekinetically assembles a pyramid in the air. This leads into X-Men: Apocalypse (2016).
When the 20th Century Fox logo fades away, the X in the logo stays for a second longer before it also fades away. The "X-Men" score can also be heard near the end of the logo.
SPOILER: In the Rogue Cut, there is a scene in the closing credits: Trask is seen in custody in Magneto's Pentagon cell.
The X-Films' title sequences features a weapon used by the villain of each film, backed by the X-Men's Cerebro device.
In this film it is Boliver Trask's Sentinel machine, which is a mixture of circuitry and Mystique's cells.