ITV's Robert Peston is out with a report from today's call between Biden and UK PM Johnson:

Call between Biden and Johnson just over. They agreed not all hope lost, there may be scope for a [unspecified] diplomatic agreement, but the situation is fragile. The call on Russia/Ukraine lasted 40 minutes

Any agreement, it seems, would include NATO formally saying it won't grant Ukraine membership and would probably also include far fewer western troops/weapons going to Ukraine. Or maybe Russia settles for less than that.

Meanwhile there's this from CBS:

CBS