There's a QG accepted and declined. My personal preference as black is to decline it and play 1 ...d5 2 ...c6. It's called the Slav defense, but sometimes semi-slave. Honestly, I don't know all the nuances of this defense. I just like the familiar structure of ...c6 and ...d5 as black since I play the Caro so often as black against e4.
White has a couple of good responses after your second move, 3. Nf3 or 3. Nc3 seem to appear the most.
If you want to be a little more flexible in response to 1. d5 you can play 1 ...c6 as black. Then if white plays 2.e4 (which is very tempting) you can play 2 ...d5 and you're in the Caro
Accepting the gambit pawn as black on move 2 opens up a whole other world that I still need a LOT of work on. :-)