I don’t know if anyone has seen this little titbit I found on filmschoolrejects:

At the very end of the movie — if you watch the credits — there’s a pin, and you see someone picking it up. The reveal would be Sam Jackson, wearing an eye patch and holding a lightsaber and he looks sort of befuddled – maybe a Frozone uniform – and he goes ‘I’m in this one too?’ And bam, cut to black.

I have almost no idea what tomorrowland is about but this would have made my day.