Baseball note: Back in July 2006, the ChiSox played a series against Boston.— Silvio Canto, Jr. (@SCantojr) January 29, 2018
It was a regular season series between the last 2 WS Champs.
Frankly, I can't think of any other examples of the last two World Series champions playing each other in a regular season series.
"Freedom is never more than one generation away from extinction. We didn't pass it to our children in the bloodstream. It must be fought for, protected, and handed on for them to do the same, or one day we will spend our sunset years telling our children and our children's children what it was once like in the United States where men were free." - President Ronald Reagan