According to some reports Marvel is interested in having Beyonce join their cinematic universe. To what capacity no one knows, but there would ultimately be some backlash and the near mention of her around a Marvel movie. While I was a bit skeptical at first I eventually realized that it could be a good thing. Right now it does appear to just be rumors, but the backlash is real. If Marvel wants to insert Beyonce here are a few roles I think Beyonce could play.
She Hulk - With Hulk solo film-gaining traction Queen B would look good as the green super powered cousin of the Hulk. Marvel could look to stage a film set around Planet Hulk, or they could just opt to place she Hulk in the mix of whatever it is they plan to do with Hulk. My vote is Planet Hulk.
Valentina De Fontaine SHIELD, HYDRA Member not a big role now but she could be boosted up in Phase 3 and Beyonce could bring her to life. The popularity of Black Widow and the surge and want for strong female characters thanks to Game of Thrones, Hunger Games, and Divergent. Valentina would be a fresh face and someone no one really heard of so her story could be told with creative freedom. She may not be an Avenger, but she could play a pivotal role in a few movies.
Namorita - She's an ally of Nova and with people clamoring for his solo film she could be in a good position to have 2-3 movies and she should bring life to the character. She was blown to bits during the Civil War, but pairing her with Nova and slowly introducing her to mainstream audience she could play a big part in the next phase. Or at the very least be a regular feature in the Marvel Universe.
Tigra - Greer Grant Nelson former detective who lost her husband and her job. She gained her powers in an experiment and later a group of mythical beings turned her into a half human half cat. She can change to and from her form using her amulet. She's a Hydra hater and once a member of various groups including the Avengers. Beyonce is perfect, she's sexy, strong, and has the backing to make Tigea mainstream. Imagine her, Black Panther, Antman, and Spider-Man leading the New Avengers. Plus I saw her crawl like a cat once in a video that was pretty hot.
Ms. Marvel - Marvel made it clear they want her to be a featured character in their cinematic world. She's been heavily promoted as the face of Marvel. Beyonce has that feminist vibe and the look of a hero. She's been fantastic as a strong female character before in Goldmember and Obsessed. Since Ms. Marvel has never been depicted on screen using Beyonce could be a great a idea. There would be backlash because she's black and a singer. But ultimately I think she would nail the part.
There you have it, a few roles Beyonce could play if she were in fact invited to join the Marvel universe.