What is happening with the Marvel Netflix shows is pretty unprecedented. Not only does Daredevil, Jessica Jones, Luke Cage, Iron Fist, take place in the same universe, but there is a very long term plan for a storyline involving all of them with The Defenders, and even more with The Punisher. This is what is known about these shows and their release dates.
According to Yahoo! Style, it sounds like those that really loved Jessica Jones (which includes myself) will have to wait a while, like until 2018. Considering that most shows traditionally space out their seasons one year apart, three years after the original first seasons is a long time.
However, this is Netflix, and when you are trying to release an entire show at once, you might have to wait until the season is complete. Part of it is that Marvel's Netflix plan is two shows per year. There is a quote from Netflix head Ted Sarandos saying "I doubt that we could produce at the quality that they produce at that speed. But we're gonna try to make them quicker so we can get less downtime between them."
Last year, it was Daredevil Season 1 for the spring, followed by Jessica Jones Season 1 in November. Since fan demand was high for Season 2 of Daredevil, Season 2 of the show was fast-tracked so fans got a chance to see it last spring. Then, on September 30, 2016, the next show in the Netflix queue is Luke Cage.
Luke Cage is about the title character, who was given a proper introduction on Jessica Jones, played by Mike Colter. Other cast members include Frank Whaley, Theo Ross, Erik LeRay Harvey, Simone Missick, Mahershala Ali, and Alfre Woodard, who will play roles as the strongman crimfighter takes on crime in Harlem. How it will tie into the current darker Marvel Cinematic Universe has yet to be seen.
So with two shows per year, what is in store for 2017? Fortunately, Iron Fist is already in production, and there was a trailer at Comic-Con showing footage from it with its star, Finn Jones. So far, there isn't much known about what will happen with this particular show, but it could tie-in to Luke Cage very well. In the original source material, Iron Fist was a partner to Luke Cage in his own title, Power Man and Iron Fist. It would not surprise me if Finn Jones made a sudden guest appearance on Luke Cage.
As for The Defenders, there are reports that this is also filming. There was also a trailer at Comic-Con, but there was no footage shown. Considering that it is going to join up all four main characters, it is possible that Iron Fist and The Defenders are filming at the same time. It is also possible that footage for Jessica Jones Season 2 is being produced, not to mention Daredevil Season 3, which currently has no planned release date. There is even less plans known about The Punisher, who appeared in Season 2 of Daredevil and the fan-favorite character was popular enough to get his own show airing soon.
It really all hinges on whatever long range plan that Marvel and Netflix have for these particular series. The advantage is that they know that these shows will join together, so it is just a matter of whether or not these actors can cross over. So far, so good, and I can't really think of any time that television has done something like this, but CW is probably going to do something similar with its DC shows.