They were occupied in 1944 by the Nazis. Hungary up to that point protected their Jewish population, but after the occupation almost all were shipped to Auschwitz.
Most Hungarians, (unlike the Jew Soros) tried to protect the Jews , but the Germans had a very dim view of that. My mother and her sister were sent by my grandmother to take milk to a nearby farm for their children(a Jewish family) the occupying German soldiers told them to leave and fired shots at them with the promise that if they came back they would be killed.