spells – Can someone see with devilsight inside a fog cloud within a sphere of darkness cast inside?

Basically what happened in a session is we had the party come up against a group of Bugbears who attacked the party in an ambush. In a moment of haste the party’s warlock cast Fog Cloud to help obscure against the bugbears to try and cause an even ground for the fight. At the same time to give their team an edge the Warlock cast Darkness on one of their ally’s blades so that they could see within the darkness and give at least two of the members who had devilsight advantage in the fight.

So my question is this, if someone cast Fog Cloud and then another cast Darkness within the cloud, does the darkness basically remove any trace of the fog within or does the people with Devilsight see nothing but the fog within the darkness?