Here's some background and inside jokes to help fill in some of the gaps for viewers who don't watch both Philly-based shows.

This matchup brought together two Philly casts: “Abbott Elementary” and “It’s Always Sunny in Philadelphia.” The crossover ...

The call was made back in 2013 to move It's Always Sunny in Philadelphia to FXX. Here's why The Gang should be honored with a return to FX.

Fan reactions to the 'Abbott Elementary' and 'It's Always Sunny in Philadelphia' crossover show that it was the strange combo ...

Willard R. Abbott Elementary School and its students, teachers and administrators are now officially part of the It’s Always ...

The ‘Abbott Elementary’ and ‘It’s Always Sunny in Philadelphia’ crossover ... this unlikely pairing will feature the “gang” as volunteers at the Philadelphia-based elementary school ...

“The Gang” is all here — and bringing absolute chaos to Abbott Elementary. The cast of It’s Always Sunny in Philadelphia made its way to the ABC show, which is set in Philly, for the ...

By Christy Piña Associate Editor “The Gang” is all here — and bringing absolute chaos to Abbott Elementary. The cast of It’s Always Sunny in Philadelphia made its way to the ABC show ...

The Gang and the Willard R. Abbott faculty finally meet in the first teaser for the long-awaited crossover episode between the two great Philly sitcoms, Abbott Elementary and It’s Always Sunny ...

Decider has an exclusive promo image and a two-minute teaser trailer that offers compelling insight into what’s in store for the It’s Always Sunny gang and Abbott’s staff. Decider’s ...