Another one that was teased in advance, Apocalypse and Coven are perhaps the two seasons that are most closely related. There are a ton of returning characters, including Cordelia, Zoe, Madison, Queenie, and Myrtle!
We also meet the male counterpart to Miss Robichaux's Academy For Exceptional Young Ladies: it's called the Hawthorne School For Exceptional Young Men. This male coven seems to be one of the main plots of Apocalypse, and the place where Michael Langdon develops his abilities.
Then there's the fact that three new witches enter the fold, all of whom are introduced in season eight. We have Coco St. Pierre Vanderbilt, Dinah Stevens, and Mallory.