Its been announced that an Agents of SHIELD spin off is in the works, there's been much speculation as to what it will be but I think the most likely subject will be the Inhumans, or rather the Inhuman/human hybrids that Medusa called Nuhumans.
First lets go back a bit. Marvel does not have the film rights to the X-Men. They sold those right to Fox years ago . 20th Century/Fox is still making truckloads of money from the X-Men so there's no way they want to give them back to Disney/Marvel.
Marvel though needs something like the X-Men. The mutants bring two great story telling benefits. The X-Men have powers that need no complicated origin story and very importantly, they are outcasts, people fear them.
So they have been building up the Inhumans to be their X-Men substitutes. A while ago the comics had a Terrigen bomb releasing the mist over the Earth so people who had the gene transformed into Inhumans. The comic book series Inhumanity was about their adventures.
Now lets jump back to the MCU. The whole second season AOS has been about people gaining powers. Specifically we have Skye & Rainia transformed into Inhumans. The result- they are feared and social outcasts. Gonzales even calls Skye a "thing" and wants to hunt her down.
The episode "Who you really are" ended with a box of diviners going missing. According to the Kree Vin-Tak, those diviners held enough mist to produce an army of Inhumans. What I expect is that we will see that army. The diviners will be the equivalent of the Terrigen bomb and the released mist will effect people world wide.
The new series will be their story. Ordinary people who suddenly find themselves "powered" , feared by the population with Gonzales's SHIELD (which I expect will eventually be HAMMER) after them. All of this will of course fit in nicely with the forthcoming Captain America :Civil War movie.