The "I Know What You Did Last Summer" on Netflix you are referring to is likely the 2020 TV series adaptation of the original slasher franchise. This series reimagines the story around a group of young people who are stalked by a killer after a tragic accident they are involved in during the summer. It debuted on Amazon Prime Video in 2021 but has connections to streaming availability on Netflix in some regions. Additionally, a newer "I Know What You Did Last Summer" film was released in 2025. This film acts as the fourth installment in the franchise, taking place 27 years after the original murders. It follows a similar plot where a hook-wielding killer targets a new group of friends after a fatal accident cover-up. The 2025 film stars new actors as well as original cast members reprising their roles and was theatrically released by Sony Pictures. So the "I Know What You Did Last Summer 20 Netflix" could refer either to the 2020 TV series adaptation or the presence of the franchise's newer works on Netflix. The 2020 show is a suspenseful teen thriller involving secrets and a killer after a fateful summer accident, and the franchise continues with a new film in 2025 that was also well noted.