As for what we’ll see in Season 2… we really don’t know.
We don’t know what kind of ground The Defenders is going to cover, so at this point we can’t really even say where we’ll find the character at the start of Season 2.
In Season 1 of Luke Cage, audiences watched as the titular hero set up roots in Harlem, tried to stop the corruption taking it over, and had an epic personal spat with his half-brother.
We certainly have not seen the last of Mariah Dillard, who was able to turn some of New York’s most influential people against the bulletproof hero; and Diamondback is in custody instead of dead, so it’s entirely possible that he could make a comeback.