Elizabeth Montgomery in The Twilight Zone (1959)

In a futuristic world a man and a woman, from opposing sides in a devastating war, meet in a deserted city. They don’t share a common language and she is quite wary of her opponent, though he doesn’t appear aggressive in any way. When she attempts to kill him, he goes off on his own. It’s obvious that society and civilization has been destroyed and she begins to reconsider.