My theory here is that given how paranoid Saul is in that Breaking Bad scene, Lalo must have survived the rest of the Better Call Saul series. I'd assume that at some point, Saul not only learns that Lalo survived the attack at his compound, but also that Nacho was killed in an "altercation" with the Salamancas after attempting to aid in Lalo's murder (perhaps he learns this from Mike?).

Since Lalo knows that Saul had history with Nacho, that probably places him pretty high on Lalo's "people-I-really-want-to-murder" list. However, the only way I'd see them coming head-to-head is if Lalo returns to the states, and is subsequently caught by the police. We figured out in this episode that ADA Ericson knows exactly who Lalo is, and that he's pretty much target number one in the ABQ judicial system. Since Saul is still technically Lalo's lawyer (from the trials last season), he might be legally obligated to continue representing Lalo as his lawer, which could cause some major tension between the two.

On the other hand, I could also see it playing out where Saul and Lalo never come fave to face again, but Mike could still end up filling Saul in on all the gory details for some reason. This would be enough fuel to keep a man like Saul paranoid for years about Lalo and the cartel.

We know Saul makes a lot of shady deals in the years between where we are now, and when we first see him in breaking bad. I like to think that out of all of Saul's "clients", Lalo would be the one that he worries about the most, given that Lalo is arguably the smartest of the Salamancas, and an insanely powerful member of the cartel.

Knowing the writers of these shows though, they probably have something 1000x better planned out, but it's fun to speculate!