Spoiler-alert! If you have seen this zombie film: Why do you think the movie is called the way it is? Think about it, before reading on. My guess is, you won't stand a chance to come up with the reason.
Originally, scientist Robert (Will Smith) does not heal his female zombie-like patient in his house, but surrenders her to her zombie-lover and the other zombies, who let Robert go. He realizes that they don't want to get healed, and that these creatures are Earth' new Human society now. Robert and the other remaining uninfected few Humans are the real disruptive force now. And they all get along happily thereafter, presumedly.
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