Understanding The Sinner season 3 ending requires delving into the philosophical core of the 8 episodes that aired in 2020, as the finale touches on many of the show's larger themes. Debuting in 2017, The Sinner follows troubled police detective Harry Ambrose (Bill Pullman) who investigates mysterious cases that often speak to the nature of humanity at a deeper and more primal level. Originally intended to be a miniseries, the show was expanded into subsequent outings that deviated from the eponymous novel by Petra Hammesfahr.

https://screenrant.com/the-sinner-season-3-recap-ending-explained/