The Twilight Zone - People Are A Like All Over

Biologist Sam Conrad is scheduled to go on a mission to Mars and is genuinely concerned about what they will find there. The mission commander, Mark Marcusson, tells him there's nothing to worry about as he firmly believes that God made everyone in his image and no matter what they find, he is certain that people are alike all over. They crash-land on Mars and Marcusson dies from his injuries. Conrad is happy to find that the people of Mars are very human-like, friendly and intelligent. They provide him with a home and promise him much more. Too late however he realizes that, just as Marcusson had said, people are alike all over.