Most likely in a post-credit scene.
According to TheWrap, Deadpool star Ryan Reynolds recently shot a scene to be featured in the future 2017 Wolverine film, Logan.
Film director David Leitch, who was recently hired to direct Deadpool 2 and replace previous director Tim Miller, allegedly directed Reynolds in the scene for Logan.
An individual close to the project allegedly told TheWrap that the Deadpool scene will most likely be a post-credit inclusion, with Fox declining to comment.
Logan will release on March 3, starring Hugh Jackman in a 2024 world as a much older Wolverine. As Logan’s healing abilities slowly start to fade away, he must cope with the loss of the X-Men by fighting an evil cooperation led by Nathanial Essex with a young female clone of himself.