There's always been a special bond between Captain America and Thor.
In Avengers: Age of Ultron, Cap. is the only one of the Avengers other than the Vision and the god of thunder himself who can even convince Mjölnir, Thor's mystical hammer to move. In the comic books this special connection is even more intense with Steve Rogers actually being able to grip and fully lift Mjölnir with minimal effort.
For as long as the two heroes have been core members of the Avengers, fans have oft speculated (read: fantasized) about the American super soldier and the Asgardian God getting down, but now, thanks to senior editor at Marvel Bill Morse, we have confirmation.
The current Thor, Jane Foster, and the current Captain America, Sam Wilson have taken up the classic Avengers' mantles for Marvel's upcoming All-New, All-Different Avengers and it would appear as if the pair are slated to be romantically involved. The Cap/Thor OTP's nothing new—peep the #Thundershield OTP community—but this latest confirmation is stirring up feelings in certain fans' hearts.
Though the kiss may not have lived up to the slash community's expectations, it's another pairing on the list of Marvel's growing number of high-profile interracial couples. Most recently, Misty Knight and Iron Fist (Danny Rand) were featured in Marvel's Secret Love anthology series as a mixed-race couple dealing with the every day humdrum of raising children, date night, and making time to fight crime.
For the time being, fans of Marvel's cinematic universe will have to make do with slashfics, fanart, and gifs that work as double entendres.