Werner Ziegler was treated at the end of season 4. Since then, Mike and Gus have been separated; the former wallowing away in alcohol amidst family trouble, the latter looking to gain the upper hand in a brewing cartel war.
In last week's "Namaste," Mike was attacked by a group of street punks and stabbed in the abdomen. He then woke up in a strange place, having received medical attention for what could have been a fatal wound. While the episode left things ambiguous, many fans had a feeling Gus was behind rescuing Mike. As it turns out, that was precisely what happened (Gus brought Mike to a small town he finances where a doctor friend takes care of Mike) and there's a very specific reason Gus wants Mike alive.
Towards the end of the episode, Mike and Gus have a conversation near a fountain dedicated to Gus' late partner Max (where the episode gets its name, "Dedicado a Max," from). "I am in a war. I need a soldier," Gus says, requesting Mike's help in his battle against the Salamancas. When asked why he went to Mike, Gus replied by stating Mike understands the concept of revenge. It's clear Mike is still perturbed about what happened with Werner, but "Dedicado a Max" ends with the idea Gus and Mike are in business together again.
After the season 5 premiere "Magic Man," it looked like Jimmy now caught up in Kim's Mesa Verde work (representing Everett Acker), it remains to be seen if Jimmy will have anything to do with the cartel in the near future. It's worth mentioning next week's episode is called "Wexler v. Goodman," so the second half of season 5 may be depicting the deterioration of Jimmy and Kim's relationship.
"Dedicado a Max" works as a reminder of Gus' primary motivation in the ongoing cartel war. , Hector Salamanca murdered Max, serving as the catalyst for Gus to plot his revenge against the Salamancas. Moving against Lalo is part of Gus' plan, and it isn't known if Lalo is alive or dead during the events of Breaking Bad. Perhaps Mike finds a way to take him out as he renews his partnership with Gus. It'll be interesting to see what transpires the rest of the season, but the pieces are in place for Better Call Saul to have an explosive last handful of episodes this season.