Lalo gotta be dead by season 4 of "BB" because Gus told Hector he was the last Salamanca.
Or so he thinks.
Walt thought for certain that Jesse was dead.
We can ask the question: "Even if Lalo remained alive, then why didn't he avenge the deaths of his cousins?
Gus' existence during the events of Breaking Bad were only 8-10 months, tops. Walt turned 50 in the opener, and turned 51 after Gus was killed...and the Salamancas were dropping during that short window as well. Lalo was probably in a position where he couldn't get back across the border...maybe he's comatose (too cliche).
I'd say there's a 30% chance that Lalo is still around. Him popping up after the BB era would be some badass shyt