Can I see my active diplomatic deals in Civ 6?

In the top/top left there is a tab called reports. Select that and in there you can see what items you are currently trading out and getting in - under the current deals tab. It's the same place you can see yields, units etc.

Here's a mod to enhance it if you really care as well. https://forums.civfanatics.com/resources/unit-report-screen.25396/

This is now slightly different in Civ 6 - New Frontier Pass (possibly in earlier expansions/updates). To view Diplomatic Deals, click the List of Reports button in the upper right, select Yields, then scroll to bottom to see your current deals.