Caleb Denby explores the Panov-Botvinnik Attack, an exchange variation of the Caro-Kann Defence that begins with 4.c4. See the continuations thereafter.
2017.08.07
Gata Kamsky vs Anatoly Karpov, Karpov – Kamsky FIDE World Championship (1996): B14 Caro-Kann, Panov-Botvinnik attack, 5…e6
http://www.chessgames.com/perl/chessgame?gid=1069346
Vassily Ivanchuk vs Veselin Topalov, Amber Tournament (Rapid) (2008): B13 Caro-Kann, Panov-Botvinnik attack
http://www.chessgames.com/perl/chessgame?gid=1488755
Arkadij Naiditsch vs. Ferenc Berkes, 2008: B14 Caro-Kann, Panov-Botvinnik attack, 5…g6
http://www.2700chess.com/games/naiditsch-berkes-r4-subotica-2008-09-04