Have relations thawed between US and Iran?

Freddy Gray is joined by Charlie Gammell, a historian and former diplomat who was on the Iran desk at the foreign office. On the podcast they discuss this week's Iran-US deal where six prisoners have been released on either side and $6bn sent back to Iran. There has been political backlash with the Republicans suggesting the Democrats are 'funding terror', but does this show a thawing of once frosty relations?