Iron Fist is the last of Marvel's Defenders (excluding The Punisher) to receive his own Netflix show preceding the cross-over series. Without getting into spoilers of the character, Daniel Rand (played by Finn Jones, Game of Thrones) has the ability to control the Iron Fist, a power that allows him to focus and redistribute his chi. Iron Fist in the past has been seen teaming up with Luke Cage in order to form the group known as Heroes for Hire. On some occasions he can be seen as being paired with Spider-Man, as the characters have some similar themes and tones.
The Netflix-exclusive Iron Fist series is said to have a lighter tone than that of its three other counterparts. More information from New York Comic Con 2016 can be found here.