Last week, New Horizons crossed the 50 AU milestone,i.e. approximately 8 billion km (5 billion miles) from Earth. That implies that it must still be in the Kuiper belt, which is 30 AU- 50 AU from the Sun, but NASA stated that New Horizons will study additional Kuiper belt objects. So what's next for the spacecraft? It crossed 486958 Arrokoth (Ultima Thule) two years ago and I haven't heard of any other flybys since then. There are many dwarf planets like Makemake, Ceres and Haumea that it has already crossed....what is the next target?
New Horizons was extended into 2021, so it will be exploring other Kuiper Belt objects. I don't think it's determined yet which ones. Alan Stern (PI of New Horizons) says the proposals for the next flyby are due January 2022 with decisions made in April 2022.