Jessica Jones has always been a show that focused on the inner emotional journey of the title character. Unlike some of the Marvel installments on Netflix, it was never interested in the Hand or the greater Defenders whole, which is why it's not surprising that neither Danny Rand nor Daredevil characters turn up, even when the script suggested they might. On the other hand, Luke Cage started off as a part of Jessica' world, so it was not a surprise he would be there at the end of it as well. Luke Cage's cameo in Jessica Jones Season 3 may have struck some as a little awkward as a send off to the Defenders, but for Jessica, it was just right.
When fans first met Jessica Jones, she was getting drunk in a bar where Luke bartended. Within a few scenes, she and the man with bulletproof skin had broken the bed. What Luke didn't know was their meeting wasn't accidental. Jessica was watching him.
After twelve episodes where various Defenders characters were referenced, finally, the world came full circle, as Luke Cage arrived on Jessica's doorstep. Dressed to the nines as befitting where fans last left him at the end of Luke Cage Season 2, Cage had a message for Jessica that the tables had turned. Luke was watching her.
Moreover, Luke Cage had put two and two together and figured out the secret masked vigilante was none other than Jessica' adopted sister Trish. As Luke had gone through this same scenario with a powered sibling in Luke Cage Season 1, he felt compelled to give Jessica some advice, namely that handling one's family business was something that couldn't be avoided. Jessica may wish someone else would come and solve her problem. But in the end, to feel right about it, it had to be her that did it.
And yet, fans had questions when Luke walked back out of Jessica's office. Commenting on his new duds, Luke noted that it was part of his new line of work. It's not the only reference to his ownership of Harlem's Paradise. When Jessica tries to insist she isn't able to go after Trish, Luke counters that she will, because she cares:
In fact, if I ever go too far, I hope someone gives enough of a sh*t to take me down.
Jessica seems slightly taken aback at the admission that "going too far" might be something Luke is likely to do. Cage shrugs: "Some would say it's inevitable."
Was this supposed to be a set up for a new crossover or a third season of Luke Cage? With no second season of The Defenders ever in the cards, chances are it's the latter, especially since Season 3 of Jessica Jones was filmed in the summer directly following the release of Luke Cage Season 2, and this scene most likely filmed before the wave of cancellations began in October of 2018.
Would Jessica Jones have come to take Luke Cage down in his show's third season? Fans will never know. But at least they got to see Luke and Jessica together for one last time.