I may have slightly jumped the gun proclaiming Joe Biden as the winner of the presidency.
There is still a chance, probably small but not impossible, that Arizona may be called for Trump. ABC news is not projecting it as a Biden win yet.
Pennsylvania, a key state for Trump, looks competitive and we will find out within the next day or two (hopefully) who has won. Also, Nevada, which is likely to end up in the Democratic camp, looks very close at the moment.
So to summarize, whilst I think it is likely that Joe Biden will narrowly win the election, I haven’t entirely ruled out Trump springing a last-minute win, particularly if you see some mail-in votes rejected should it go to the courts in the coming days and weeks.