World War III, also known as the Third World War, is a hypothetical future global conflict subsequent to World War I (1914–1918) and World War II (1939–1945). It is widely predicted that such a war would involve all of the great powers, like its two predecessors, and the potential use of nuclear weapons or other weapons of mass destruction, thereby surpassing all prior conflicts in scale, devastation, and loss of life. World War III was initially synonymous with the escalation of the Cold War (1947–1991) into direct conflict between the US-led Western Bloc and Soviet-led Eastern Bloc.
https://en.wikipedia.org/wiki/World_War_III