Just finished up Season 4 of Gomorrah over the weekend.
Followed the same path as referenced by draxen here after watching ZeroZeroZero on Amazon, which I thought was great.
I think Gomorrah was better. It’s quite the ride. Looks like there will be a Season 5, which the show runner thinks will be the last.
Also, in looking up whether there’d be another season, I came across that there was a film as well that covers Ciro’s backstory and also hints at being some kind of bridge in to Season 5. Unfortunately, it can’t be streamed anywhere so it looks like I’ll have to pick up a copy off ebay.