Ben (Jay Ryan) and Bev (Jessica Chastain) are now in love, while Bill (James McAvoy) goes home to write a brand new novel, which hopefully has an ending that doesn’t suck. Most poignant, though, are the endings for Mike and Richie (Bill Hader), as the former finally leaves Derry for the first time in 27 years, and the latter carves his initials with Eddie’s, as a way of mourning an unrequited love.
Article source: https://www.cinemablend.com/news/2479317/it-chapter-two-ending-how-its-different-than-the-book