They Both Die at the End by Adam Silvera
Two MCs of this book, Mateo and Rufus, both get a call that they are going to die that day and so they join this app called “Last Friend” and they meet each other and go on this adventure around New York City and they just talk and live their last day together. Even though the book does have a sort of dark title and there are those elements of death constantly woven throughout the story. It is mostly a story about hope and about life and living and everything that comes along with it. The book also has chapters told from random side character’s point of view and how they are choosing to live their day off they got the call or not, and it is cool to see how everybody is interconnected in the world.