ML for healthcare. The whole industry is so far behind everything else, it is not even funny. Problem is, Just like Airbnb or Uber, the biggest road blocks are not technological, they are organizational and political. It is entirely possible, we might need some major privacy / security related leaps in ML to convince the medical industry to adopt it fully.

ML in movies and rendering. Deep Fakes is just an amateur's tech demo. In a few years, I expect to see render rights actually become a thing. Like, you don't act in the movie, but give a company rights to use a 3d render of you in it.

real time and full time holograms / AR. With remote work becoming a thing, I see a huge market for full 3d renders of the person presenting or even completely virtual AR work places where people check in to work. Maybe not for a decade or two, but whoever builds the flagship product will make a ton of money.