Hillary Clinton has run for president two times, in 2008 and 2016. After announcing in 2007 that she would seek the Democratic Party's presidential nomination for 2008, Clinton began the primary season as the front-runner; ultimately, however, she failed to garner enough delegates to overtake Barack Obama, who went on to win the general election. In April 2015, Clinton announced that she was entering the U.S. presidential election race of 2016, and she immediately became the favorite to win the Democratic nomination. However, her campaign faced an unexpected challenge from Bernie Sanders.

Source: Britannica