According to reports, Kevin Feige is not keen on casting Defender, a favorite character of the audience.

Fan service has always been a priority for Marvel Studios, which is why some of the performers from the Marvel programs on Netflix were welcomed back. Fans anticipate that the co-stars from the red and black streaming platform will join Charlie Cox and Vincent D’Onofrio, who have already started their MCU journey in Phase Four. But it seems that not everyone from the Defenders universe will be granted access to Earth-616.
Surprisingly, it seems like a fan favorite actor won’t be joining the MCU. Luke Cage actor Mike Colter is “almost probably” not going to be a part of the multibillion-dollar franchise, according to a revelation from Giant Freakin Robot. Despite the actor’s popularity, Kevin Feige is supposedly not interested in casting him, according to the outlet’s source.
A new Iron Fist actor has to be found, contrary to earlier rumors that Finn Jones wouldn’t be joining Charlie Cox and Krysten Ritter in the MCU.
Of course, it’s always better to take these speculations with a hefty grain of salt as nothing has been formally verified yet. Personally, I don’t buy that since Colter has built up a fan base as Luke Cage and it would be unethical of the studio to deny him the opportunity to portray the role in the MCU.
As for Jones, Feige undoubtedly lost interest in him due to the unfavorable reviews of his Iron Fist series, but I suppose we’ll just have to wait and see how they’ll approach the Defenders.
In the anticipated spring 2024 release of Daredevil: Born Again, Charlie Cox will reprise his role as the Man Without Fear.