Meeting for the first time: US Vice-President and Democratic candidate Kamala Harris (right) shook hands with former US president and Republican candidate Donald Trump during a presidential debate in Philadelphia, Pennsylvania on Sept 10. The two debated over key issues, including the economy, immigration (移民) and US foreign policy. Harris highlighted her plan to build an “opportunity economy”, while Trump defended his tariff policies and focused on immigration concerns. According to a poll by FiveThirtyEight, an American website that focuses on data-driven analysis, Trump's likelihood of winning noticeably declined after the debate.