This Zippy the Pinhead strip from a week or so cuts to the core of the canonical joke pattern in comic strips:
What's interesting to me about this is the choice of descriptors here. "Conflict" and "punchline" here have to do with joke telling, and could correspond to varying parts of an actual narrative arc.
For example, narrative often features a denouement at its end preceded by the Peak of actions. The Punchline could go into both Peak or denouement. In one case, the Punchline would be the apex of the actions, what the strip has led up to. In the case of a denouement, the Punchline would be a reaction to or resolution of that Peak.
So, what we actually have is two separate "schema" for narrative and for jokes:
Jokes: Intro-Set up–Conflict–Punchline
You could imagine these running parallel to each other, and then different parts hooking up into each other in varying ways. How exactly these schema interface depends on on the desired pacing of the joke I suppose.