Persons Of Interest season 5 finale found Team Machine making their last stand against Team Samaritan and successfully taking down the evil AI that was threatening to take over the world. However, this victory came with a major casualty.
Spoilers from POI season 5 finale episode ahead
In episode 13 titled, Return 0, John Reese died heroically while uploading a copy of The Machine to a satellite, thereby saving the world. Harold Finch was the one prepared to make that sacrifice, but Reese tricked and sent him to the wrong building, and saved his friend's life. The AI reached out to Sameen Shaw, thereby making him a potential Reese successor.
Executive producer Greg Plageman and creator Jonathan Nolan spoke to Entertainment Weekly about killing off Reese in episode 13. He said, "This is kind of the most poetic ending for John Reese. If you really look back on the season, you can really see the foreshadowing of what was coming."
Nolan, however, believes that killing Reese off would bring his story and that of Harold's full circle. He explained, "When we meet Reese in the pilot, he's in extremis and is going to hurl himself into the East River or shoot himself or something, but the pilot begins with Finch saving Reese's life (and Carter, who is an important part of that as well). The pilot begins with this relationship between these two guys, and Finch reaches out and says, 'You need a purpose. So, the symmetry in the end of having Reese saving Finch, for us, was very moving."
Plageman added to the topic and said, "There was no one else in his life at the time, but Harold Finch did have someone and John Reese understood intuitively that it was more critical that Harold continues on and live the life he's never been able to have with Grace."
In a separate interview with Deadline, Plageman discusses a potential Person Of Interest follow-up/ or a spin-off series. He said, "Look, I think the premise that Jonah came up with in terms of an artificial intelligence that takes in all this information, processes it and gives, you might say, a predictive output in some regard is so strong that there's no doubt that that could be revived in some sense."
The producer hinted that the show could come back in a different form. "I don't know if it would be with these characters. In episode 11 this year we understood that the Machine had been providing information to another group of people. So could it be that this show is strong enough that it could come back in a different form? I would say never say never in a world where we've seen the X-Files and 24 and a number of really strong premises come back as well."