Have there ever been any shows in which in-laws have gotten along with each other? Brothers, sisters, spouses, whomever?

there was "PETE N' GLADYS" in the late 50s, for one. That's all that I can think of right now.

Oh, no! Just thought of another one "FRIENDS". Chandler got along with Monicas parents.

Niles Crane got along with his Mother in law on Frasier.
On The Mothers-in-law the Buell's and the Hubbards got along, the wives sometimes bickered but didn't hate each other.