The Unetaneh Tokef melody that we sang together on Rosh Hashanah and we’ll sing again on Yom Kippur was composed by Israeli songwriter Yair Rosenblum, inspired by a kibbutz’s heavy losses during the Yom Kippur War. In 1990, Rosenblum visited Kibbutz Beit Hashita in northern Israel, which lost 11 members during the 1973 Yom Kippur War. During his visit, he was inspired to write this melody to Unetaneh Tokef and stayed up all night composing it. The tune is unique in that it contains Ashkenazi, Sephardi, and modern Israeli musical influences.
You can read more about the history of the tune in this Times of Israel article.
Find a stirring performance of Rosenblum’s piece by the Israeli Defense Force’s chief cantor here.