From Medusa'a long Red hair, to the fact that the King Black Bot cant even speak. This is Inhumans. For those that don't know, let me explain a bit and try not to give out too many spoilers.
Inhumans live on the moon in a secret place that is hidden away and not known to anybody on earth. However, they are kinda like mutants in a way. If you think about it. They all have different "gifts". King Black Bolt has a very strong voice as well as vocal cords. However, whenever he tries to use his vocal cords, they make the sound and possibly destroys things, so in other words, he cant talk. Unlike Banshee from the X-Men who can control it.
Medusa has long red hair that actually grows and does what limbs and hands can and is that strong. Like pick up a car strong.
Anyway, several of the Inhumans want to go home, to Earth. Were they were a while ago before they were hated and forced to move away. They still wish to go back but fear that they will be misunderstood and hated and killed for they way they are and their powers, however they don't know about the Avengers or mutants at this point.
Any who, the major difference between the mutants and the Inhumans is that Mutants were born with a gene "Defect" That gives them all different abilities as well, like the famed Wolverine claws, or Prof. X's great mind.
Or even Gambits exploding cards. They all had a defect that showed up and was able to take over their lives and people hated them and killed them, yet they love them for saving their lives when needed. I still don't understand that part.
The Inhumans were exposed to a type of gas as they call it. The Terrigan Mist. A powerful gas like mist that appeared at the time that the Inhumans roamed the earth. Until it left not too long after. In the show it started to appear once again causing more inhumans. However it isn't good for the Mutants under the atmosphere.
And that is how they get their powers. However, in the comic books they eventually visit Earth and help the Avengers with things as well as see their own world as it is today. Black Bolt even becomes part of the Illuminati during the whole Dark Seige event after the Secret Invasion series when you realize how many people are Skrulls and not dead. Plus Thor comes back to help, But then Norman Osborn comes back to take over everything.