There's been a new rumor about Doom just about every week since Marvel got the rights to the FF and X-Men characters. One speculates that he will make a cameo in the Loki series or Doctor Strange 2, etc. I wouldn't mind if he's teased during the closing credits but I really don't consider him a Black Panther villain. I have long been disappointed that other MCU properties have appropriated things from FF lore, like Tony Stark discovering time travel, which was brought in the the MCU very early on when Doom used his time platform in FF#5. I'd hate to see another MCU character steal away their main adversary