You ask me, I think it's not just a rumour. MK will be getting a show some time soon. Let's look at the "clues" thus far:
1) This is the only rumour that's still up in the air. The F4 one was shut down, and the Hulk one confirmed. So it says something when this sits somewhere in the middle of it all.
2) MARVEL's been trying to make an MK show happen since 2006, so it's definitely on their minds.
3) Warren Ellis has said time and time again, that the only reason why he was brought in to write the first 6 issues of the new vol, was to make MK a profitable IP. Or, as he put it, make him able to build upon. That sure sounds like something's being planned.
4) Axel Alonso (Marvel's EiC) has said a lot of times that they have some big things in store for him.
5) There was another rumour a while back, saying that Netflix's Phase 2 would be: Spider-Woman, Deathlok, Punisher, Blade and Moon Knight. Never confirmed, so it's still up in the air.
6) Stan Lee's legit account shared the news. Sure, it doesn't mean anything, but you've got to admit, it's something.
7) In TWS, during Sitwell's "interogattion" he mentions a man in Cairo. What else Marvel character could be in Cairo and be important enough for HYDRA to target along with Doctor Strange?
8) Now this is the one "piece of evidence" that made me think. See, in the end of Season of Avengers Assemble, there's a bit at the end, where Tony and Cap take a look at the screen, looking for potential recruits. What pics show up around the globe? Captain Marvel, Black Panther, Doctor Strange, Spider-Man and yes, Moon Knight. All of these characters are getting a movie sometime in the next few years, all except MK, so why put him in there? We all know that Marvel ties-in their cartoons/mobile games with their movies, so this is at least a hint. It doesn't make much sense, I mean, why add a B/C-Lister along with Spider-Man and the next movie stars if you're not going to do anything?
Now, does any of these bits and pieces of "news" mean that MK is getting a Netflix show 100%? Well, no, that's absurd. But it's being strongly hinted at if I say so myself. Besides, the character is suited for Netflix. Heck, they can even skip the costume and just make him wear his white suit (Mr. Knight) to save some cash. It's literally the one property that can be done both faitfully and "cheaply".