The Battle at Lake Changjin (2021)
I went on a bit of a research expedition and learned that Mao’s eldest son, Mao Anying, who was killed in 1950 by a US bomber during the Korean War briefly depicted in the movie, studied in Moscow, petitioned Stalin to send him to the front during the WW2, got his wish, and served as an artillery officer, during the final Battle of Berlin including. Also had no idea Mao had 10 children lol
Stalin’s second son, Yakov Dzhugashvili, also died during WW2. He was captured by the Nazis and they tried to use him as a bargaining chip, but Stalin rejected their offers since no other Soviet POW would get the same treatment. The Nazis probably executed Yakov in 1943 after that failed.