This Is Us: The Pearson Family Is Undergoing a Lot of Changes in Season 4

While Toby and Kate's relationship has been fun and lighthearted up until now, things will start to shift now that they are parents. "We've seen a lot at the surface with stuff, and things start to get a little more serious and they realize that it's not all fun and games," Chrissy Metz told Good Housekeeping. "We [Kate and Toby] can't protect ourselves with humor and sarcasm."