Marvel Studios' head honcho Kevin Feige has confirmed that Charlie Cox will play Daredevil in the MCU. Feige made the reveal during an interview with Cinema Blend.
"If you were to see Daredevil in upcoming things, Charlie Cox, yes, would be the actor playing Daredevil. Where we see that, how we see that, when we see that, remains to be seen."
- Kevin Feige via Cinema Blend
While Feige makes it sound like we won't see him for some time, I believe he will make an appearance in Spider-Man: No Way Home. This arm from the first trailer is a Charlie Cox arm, I won't be swayed otherwise.
Cox played Daredevil on the Netflix MCU shows Daredevil and The Defenders. It is a great development for fans of the Netflix Marvel shows, as this acts as one of the few times where the shows actually tie into the MCU at large. The shows (Daredevil at least) were very popular on Netflix. The last Marvel show to appear on Netflix was 2019's Jessica Jones season three.
There is now hope for all of the other characters on TV shows "in the MCU" to actually show up. I'd love to see Ebon Moss-Bachrach return as Micro, personally. I feel like his advanced programming and motion tracking tech would be very useful once the multiverse is ripped open. What characters from the small screen would you like to see return?