e4 c6 d4 d5 takes takes c4!

how to continue?

1.e4 c6 2.d4 d5 3.exd4 cxd4 4.c4 Nf6 5.Nc3 and now Black has many good systems:

5...e6: The main weapon of Karpov. It's a typical Isolani-structure. The player who better understand it, wins.

5...g6: Black is playing the Rubinstein-System against the Tarrasch, but of course with a tempo down, so it's a pawn sacrifice, but a sound one. OTB this variation should be a bit risky.

5...Nc6: The modern mainline and also the favourit of GM Dreev. Black has nothing to fear in this line. He needs only to know the theory.

5...Be6: Not a very good line, but a good suprise weapon.

Currently the Panov-Attack is out of fashion.

I believe that after e6 white has c5?

Yes, that's correct. But it's not a very good line.

Best notation ever. I think Nf6 is the main move isn't it? It's not an opening that requires lots of theory knowledge, just positional understandings

I think the Panov-Botvinnik attack in the Caro Kann requires black to play rather accurately, which is going to be hard at our level