Last election- 2016- mail-in ballots were hardly even counted. But, due to the pandemic, it is extremely crucial to count every mail-in ballot, from voters who cannot come in- person. Seeing this, some research was done.  The 4 battleground states- Pennsylvania, Nevada, Wisconsin, and Georgia- are starting this Wednesday morning with "tens of thousands of absentee ballots uncounted". Seeing that Pennsylvania and Georgia are leading to President Trump, they might turn blue. Pennsylvania, one of the crucial states- other than North Carolina- that President Trump needs, can help Mr. Biden win if it turns blue. He won't even need to win Michigan or Georgia. Nevada is most likely to be won by Mr. Biden, and Wisconsin also looks like it might. With Pennsylvania, Mr. Biden might just win. This is the same as Georgia. It's a very CLOSE race in Georgia, and these ballots may make a change and win needed. 

https://www.cnn.com/2020/11/04/politics/mail-in-ballots-pennsylvania-georgia-michigan-wisconsin/index.html