The closest thing we are ever going to get to trump offering a concession just occurred. His latest tweet (written for him by his staff) just told the GSA to go ahead and cooperate with the Biden transition. He claimed that he was going to "soldier on" with the legal challenges. But it was a hollow threat. His tweet said it was time to start cooperating.
Its official, Biden is the President-elect. All that is left is to see how much damage and havoc trump can bring to bear on the country as he tucks his tail and slinks off.