Here is a map I made. I took the liberty to give Trump all the states in which there are polls showing him ahead. (IIRC.) All he needs is 10 more points to get him to the finish line, which can come in a number of forms.
I'm not trying to show that Trump is winning. Pollsters have him down in some of the state's I've given him. I'm just trying to point out that he can win without it being against all polls. There is reason for Biden to be doing all he can.