Final answer:
Based on the provided information, healthcare is the biggest issue in the upcoming presidential election.
Step-by-step explanation:
Based on the provided information, it appears that the biggest issue of the upcoming presidential election is healthcare. According to a CNBC article, healthcare topped the economy as the biggest issue for voters in a previous election. Additionally, the COVID-19 pandemic was a significant factor affecting voters' decisions, with 17% of respondents in exit polls indicating that it was the most important issue. Therefore, healthcare seems to be a major concern for voters in this election.