From a Washington Post story by Jeremy Barr headlined “Why CBS News held its Brittney Griner scoop for a full week”:

CBS News broke the news Thursday morning of WNBA star Brittney Griner’s release from a Russian prison in exchange for convicted Russian arms dealer Viktor Bout — but it came a full week after its journalists learned about it.

After receiving an initial tip Dec. 1 that Griner would be part of a prisoner swap, CBS reporters obtained confirmation from five sources by the following day. But the network agreed to a White House request to hold the news — for fear of jeopardizing the delicate negotiations that led to the swap.