Tattoos
This is another one for the hardcore fans and something that crosses over several of the Marvel films. In the MCU, the Ten Rings is a terrorist organization whose goal is to destroy world peace. Tony Stark defeats them at the end of Iron Man 3, or so we think. This photo seems to say otherwise, however.
During a scene in Ant-Man, we see that one of a group of terrorists has a Ten Rings tattoo on his neck. This would seem to imply that the nefarious organization is not quite as out of commission as we have been led to believe. I wonder if it will crop up somewhere else in the Universe?