Can you give me an example of someone who is "regarded as" having a disability?

Sure. A man, who is in line for a promotion, has a history of cancer treatment, although his cancer is in remission. He is not given the promotion because his bosses are worried that, if his cancer returns, he won’t be able to do the job. He does not, at this point, meet the first part of the definition of disability because he does not have a physical or mental impairment that substantially limits one or more major life activities. However, based on his “record of” a disability, he is being discriminated against.