At the moment it seems highly likely that the amount of Electors assigned to Biden will be 270, as he wins Nevada, and Trump wins Pennsylvania, Georgia, and North Carolina.
Assuming such is the result, this does not warranty Biden the presidency, as 202 of those 270 can technically go faithless. Some might incur penalties, but the vote would be counted as casted. Only 68 of the 270 would have their vote canceled if they voted for anyone other than Biden. As such, Biden could get less than 270 votes in the Electoral College, which would trigger a Contested Election.
A Contested Election would be decided by the new Congress. The House of Representatives would elect the President and the Senate would elect the Vice President. At the moment, a Republican majority in the Senate seems very likely, so Mike Pence would probably be re-elected Vice President in a Contested Election.
Though the Democrats are projected to have a majority in the House of Representatives, a Presidential Election in the House does not allow one vote per Representative, but rather one vote per state. Thus, the Representatives would have to vote within their state’s delegation to decide how the state will vote.
Looking at the elections for Representatives which are already called, and assuming the party members would vote for their candidates, Trump would be re-elected President, as the Republicans have a majority in 26 of 50 delegations. The Democrats only have clear majorities in 18 delegations, and 6 states are still unclear.
Thus, any one of 202 individuals could change the course of history by negating Biden the Presidency and handing it to Trump. If there are no Faithless Electors in Biden’s camp, it will be very remarkable in itself.