Writer-director Mike Mills (“Beginners,” “20th Century Women”) is back after a 6-year-break with this contemporary odyssey about a roadbound journalist (Joaquin Phoenix, sans Joker make-up but in full shambling mode) and the 9-year-old nephew (the exceptional young British actor Woody Norman). As the pair venture out to take the pulse of America, they come to learn a lot more about each other, and themselves. The film is notably shot in gleaming black-and-white by the Irish cinematographer Robbie Ryan (“The Favourite”).