The special was a variety show that had a number of live-action segments, as well as some animated portions.
The Star Wars Holiday Special involved Han Solo bringing Chewbacca back home to Kashyyyk so that he can celebrate Life Day (the Wookie version of Christmas) with his family.
Needless to say, the cast has tried to avoid mentioning this little treasure for years.
Said family contained his father Itchy, his wife Malla, and his son Lumpy, all of whom were never mentioned ever again in the main Star Wars timeline (excluding Legends, which is no longer canon).