Two cameos in fact! The first when he <spoilered> and the second in the post credits. It really was pretty cool.

It was a fun movie, at least. On the MCU scale it ranks above Iron Man 2 at any rate. I'm beginning to think that the MCU movies are now buckling under their own weight. The first ones were great because they were, literally, down to earth, and their was room for the characters - the people-behind-the-mask - to grow as people. Now it's seemingly all-cgi-action-all-the-time with little room for character arcs.