The American Community Survey is a legitimate survey conducted by the Census Bureau. Unlike the every-10-year census, this survey continues all year, every year. The ACS provides information about the social and economic needs of your community every year.
The Census Bureau conducts over 100 surveys other than the 2020 Census. If your address was selected to participate in one of these surveys, they may call you to participate. Some surveys are done exclusively by phone. They might also call you if they do not find you at home or when a personal visit is not convenient.