No one ever accused Marvel Comics of ignoring a fad. In 1972 one of those fads was Blaxpoitation, a film genre that Wikipedia says was "originally made specifically for an urban black audience, but (whose) appeal soon broadened across racial and ethnic lines". They're talking about Shaft, Superfly, Foxy Brown, etc. These movies were really talking off, bringing in an audience that didn't traditionally go to theaters. Marvel wanted in on the action and along came Luke Cage: Hero for Hire, the first African-American superhero to headline his own comic book series.
In the comics, Carl Lucas was in prison for a crime he didn't commit. A scientist working on recreating the same experiment that created Captain America recruited Lukas to participate. What do you know, Lucas ended up with super powers. Enhanced strength and unbreakable skin to be specific. Lucas used his new powers to escape from prison, and set himself up as a hero or hire, changing his name to Luke Cage (later adding Power Man to seem more like a legitimate superhero) and helping anyone who could pay his fee.
Martial arts movies were hot in the 70s, too. So Marvel introduced Danny Rand, AKA Iron Fist. The son of a wealthy businessman, and inheritor of a magical, glowing right hook, Iron Fist didn't seem to have much in common with Luke Cage. But with both their comics lagging in sales, Marvel did the only thing they could. They paired the two up, creating an unlikely new comic series, Power Man and Iron Fist. These guys were a great team though, officially incorporating Heroes for Hire into a business. They lasted for a few years until their popularity waned and the series was canceled in 1986.
Jump to 2001 and Brian Michael Bendis' new series Alias, starring Jessica Jones, a one-time superhero and current private investigator whose one night stand with a reintroduced Luke Cage eventually led to one of the longest running and most realistic relationships in Marvel Comic history.
Last year, Netflix aired its terrific Jessica Jones television series. This month they'll premiere the highly anticipated spinoff based on, you guessed it, Luke Cage. The previews for the show look great. Hopefully the new series is one more in a line of well-made movies and TV shows proving that, despite Marvel's involvement, superheroes are more than just a passing fad.
Collections of the early Luke Cage stories are hard to come by, but you can place a hold on the Essential Power Man and Iron Fist Volume 1 and Volume 2. While you're at it you should take a look at Luke Cage: Avenger, a modern retelling of his origin story, and Luke Cage Noir, a reimagining of the character set in 1930's Harlem