We saw in the finale that Saul had taken the "out" with his contact and received a new identity and would be found in Nebraska. Bob Odenkirk had some information about the potential Better Call Saul has:
"Well, I’ve talked to Vince (Gilligan) and Peter (Gould), who are writing and creating the series, about this and I’ve said that a lot of people do want to see what happens to next to Saul. So, I don’t know what they’re going to do. I know they’ve talked about prequel, but they’ve also talked to me about sequel, and they’ve also talked to me about a mix of prequel and sequel."
I wouldn't be surprised to see the show venture a bit into the future. The way they left us with Jesse would be interesting to see.