I can tell you here in Philly, it's very Democratic. They will vote Democrat even against their best interest. But the leadership of Gov. Wolf, Mayor Kenney and DA Larry Krasner has people starting to get pissed with the Democratic leadership here in Philly and the close suburbs. Obama in 2012 got 588,000 votes in Philly vs. 96,000 for Romney. In 2016, Hillary got 560,000 vs Trumps 105,000. My guess is Trump beats the 105,000 votes here in Philly. Does Biden get more than the 560,000 Hillary got? His ceiling is Obama's 588,000 but I don't think he sniffs that. At best you could see a return of the results of 2008 where Obama got 574,000 votes vs. 113,000 for McCain. So basically, a negligible increase for Biden at best, but I'm not sure Biden reaches 570,000. Looking at the results maps in PA the areas north of Philly matter more. They were blue for Obama and red for Trump.
EDIT: Trump won PA by 78,000 votes. Biden is going to need way more than a bump in Philly. Gov. Wolf is doing his best to get people to vote Republican in November.