Sunday on PBS News Weekend, polls show Vice President Harris gaining ground in key swing states ahead of this week's Democratic National Convention. We get the latest from the NewsHour team on the ground in Chicago. Then a look back at the chaotic 1968 Democratic convention in Chicago. Plus, why a device used to treat a deadly heart condition is under scrutiny. PBS News is supported by - https://www.pbs.org/newshour/about/funders