This took me a lot longer to answer because it really forced me to think what I'd want in a sixth season of Person of Interest, like if I had the energy to write a virtual season or even a wish list for what a sixth season would look like:
- Exploring the world Harold Finch left behind, a little like what happened in Mr. Robot season 2 but this time from a point of view of the hackers who are waking up to the prospect that something really weird happened. Conspiracy theories abound: About the missile that hit downtown New York, about the mysterious billboard messages in Time's Square.
- Weird things keep popping up, whispers about a prison in Johannesburg that was discovered to run illegal tests on people, and a possible emergent AI. One group, in particular, is running around proclaiming the Robot Overlords have arrived, they hack people and play Robin Hood.
- Exploration of Sameen Shaw as both Primary Asset and Primary Analog Interface, and the mysterious leader of Team Machine, International (ala Leverage Inc, International) but Shaw doesn't interfere unless she needs to. She only steps in when it's needed, mostly she's okay running her own missions, primarily making sure Samaritan hold outs are taken out.