Dictator of Cuba who made an alliance with the Soviet Union

Fidel Castro Ruz.

Explanation:

Comandante Fidel Castro Ruz was the top leader of Cuba after his guerrilla movement overthrew US-backed dictator Fulgencio Batista and took power in January 1959. In the early 1960s he took a more radical turn and made Cuba a communist country allied with the Soviet Union, confronted the USA, which imposed an embargo that remains in force largely. Castro held absolute power until he stepped down due to illness, some years before his death in 2016.