https://www.chess.com/events/2021-candidates-chess-tournament/03/Giri_Anish-Vachier_Lagrave_Maxime
https://www.chess.com/events/2021-candidates-chess-tournament/04/Caruana_Fabiano-Nepomniachtchi_Ian
https://www.chess.com/events/2021-candidates-chess-tournament/06/Wang_Hao-Vachier_Lagrave_Maxime
https://www.chess.com/events/2021-candidates-chess-tournament/09/Grischuk_Alexander-Nepomniachtchi_Ian
These are all Exchange Variation games:
Main Line 5. e4: (3 games)
5. Bd2: (1 game)
Grünfeld Defense: Double Exchange (3 games):
Classical Exchange 7. Bc4: (2 games)
Modern Exchange 7. Nf3: (1 game)
https://www.chess.com/events/2021-candidates-chess-tournament/03/Giri_Anish-Vachier_Lagrave_Maxime
https://www.chess.com/events/2021-candidates-chess-tournament/04/Caruana_Fabiano-Nepomniachtchi_Ian
https://www.chess.com/events/2021-candidates-chess-tournament/06/Wang_Hao-Vachier_Lagrave_Maxime
https://www.chess.com/events/2021-candidates-chess-tournament/09/Grischuk_Alexander-Nepomniachtchi_Ian