MCU: 10 Fascinating Facts About Captain America: The Winter Soldier (2014)
2. There's A Sneaky X-Men Reference
It would be a further four years until Marvel could even broach the possibility of using the X-Men in the MCU, but The Winter Soldier actually managed to include a sneaky reference to one of the teams from that corner of the Marvel Universe.
In the comics, Department H is a Canadian agency that headed up the country's superhero program. They were also originally responsible for Wolverine's adamantium graft, and later headed up the creation of Alpha Flight, Canada's own answer to the Avengers who've been synonymous with the X-Men for sometime.
The group only gets a passing mention in Winter Soldier during a conversation with Black Widow, but the Department would later be revisited in Agents of S.H.I.E.L.D. There, it is explained that the MCU version is still a Canadian branch, so might it even be possible that this is how Marvel will introduce some mutants into their onscreen apparatus? One can only hope.