During an interview, Kevin Feige assured everyone that there are LGBTQ characters involved in the MCU.
According to NME's report, quoting The Playlist, Kevin Feige was asked if there were any LGBTQ characters on their way in the Marvel Cinematic Universe, and not only did he confirm, yes, there was some on the way, but that we've already met one.
"Both ones you’ve seen and ones you haven’t seen" was his exact answer.
When 'Thor: Ragnarok' was released, Valkyrie's character, who was played by Tessa Thompson shared back in October that Val was bisexual, and she cares little about what men think of her - so looking at that, she must be the character that Kevin Feige means exists that we've met already.
She's bi. And yes, she cares very little about what men think of her. What a joy to play! https://t.co/d0LZKTHCfL
As far as the character we haven't met yet - it's been noted that they don't believe that we will meet any in 'Ant-Man and The Wasp,' despite it being set in the San Francisco area. That film is slated to release July 6, so the most potential would be one of the 'Avengers: Infinity War 2' (not the real title, we don't have one yet) characters may be part of the LGBTQ+ community.