When comedians come on as guests on podcasts, do they get paid for that???

OP, I'm a podcast producer. To answer your question specifically of comedians, 98% of the time, no. They're usually given ample opportunities to promote their own projects, tours, and cross-promote their own podcasts. Although sometimes their travel expenses can be offered to be picked up. If the podcast has a large following, it's free promotion for them.

Generally the only guests that are paid are experts in a particular field relevant to the topic (happens frequently on true crime podcasts).

I always gift guests a nice gift certificate/card or goodie bag though, regardless if they are compensated or not.

They're paid in exposure. And podcasts aren't these silly little side gigs they used to be, some of them are huge now.

I always assumed there was some unspoken reciprocity going on. Comedian A goes on Comedian B's podcast, 8 months later. Comedian B goes on Comedian A's podcast. Everyone makes money in the end.