Yesterday, a Disney fansite called The DisInsider reported that characters from Big Hero 6 would be making their live-action debut in the MCU. However, that information has since been debunked. Originally, The DisInsider claimed that Big Hero 6 members Hiro and Baymax would make their live-action as esteemed members of the MCU, but that ain't happening.
While it would have been cool to see either character fight alongside heroes like Thor, Spider-Man, Ms. Marvel, or Captain Marvel, fans of the electronics genius and his inflatable medical robot bodyguard will have to stick to fanfiction for their dream to come true. That's not to say that members of Big Hero 6 won't make their live-action MCU debut down the road, but for now, fans will have to be satisfied with experiencing Hiro and Baymax in animated form only.
As it happens, Disney just wrapped Big Hero 6: The Series, which features much of the voice cast from the original film. Additionally, Walt Disney Animation Studios is in the midst of prepping the TV series Baymax for Disney+. My advice is to never lose hope with regard to Big Hero 6 getting a live-action adaptation. Disney appears to be quite fond of the diverse superhero team, and so long as fans keep showing their support, there's a chance that Big Hero 6 could become a part of Marvel's next phase of the MCU.