Hillary Clinton and Donald Trump during their final presidential debate in October 2016.MARK RALSTON/AFP via Getty ImagesKamala Harris and Donald Trump will meet for their first debate on Tuesday.Hillary Clinton, who debated Trump in 2016, said Harris should lean into her prosecutor experience.Clinton argued that Trump could be "rattled," pointing to their heated debate in 2016.Former Secretary of State Hillary Clinton has some advice for Vice President Kamala Harris ahead of the Democratic presidential nominee's upcoming debate with former President Donald Trump.Clinton, the 2016 Democratic presidential nominee, jousted with Trump during three high-stakes debates that year.