You must be reading this post with a lot of hope for your Prince Who Was Promised. Sometimes the heart sees what it wants to see and as a loyal fan, I would presume you also want Jon Snow back. Without wasting time let's get into the reasons why Jon Snow will return.
1. Jon's Eyes
I know he has pretty eyes, but that's not what I'm talking about. What I'm saying, is as the camera zooms on Jon in the final episode of Season 5, you can see that the color of his eyes changes a bit lighter. You can probably guess that he has warged into Ghost.
2. Our Very Old Melisandre
I know that you probably hate her for her misdeeds, but you are aware of her power. You might have also known that priests of R'hllor have the power to resurrect people, yeah? It has even been shown in both the books and the show that they have the capability to do so. And Melisandre is present at Castle Black at the most opportune moment. If Melisandre resurrects Jon Snow, I'm probably thinking you and I would definitely forgive her.
3. Kit Harrington
The last clue is the directors and the actor have said that Jon Snow is dead and all that, right? Then I would like to know why the actor Kit Harrington was spotted with his locks in a long, very Jon-like fashion in Wimbledon and was then spotted in Belfast where Season 6 is currently filming.