If you had enough text, audio and video data on one person, you could train an ML model on that data and essentially recreate that person. It would be able to speak like them, look like them, respond like them, and eventually even think like them. All of this in perpetuity. 

I don’t know whether this is a good thing or not but that’s as close to immortality as you’ll ever get short of reversing aging. My hunch tells me it’s not healthy - death is part of the process and people need to grieve and let go. But, there could be a future where people “live” forever in this shape and form. The more advanced things get, the harder it’ll be to tell you from real you.