White has more space and is unwilling to trade. This move  is highly appreciated by the former world champion. Nepomniachtchi is  deviating from a recent game.
1. c2c4  1... e7e5  2. b1c3  2... f8b4  3. c3d5  3... b4e7  4. g1f3  4... d7d6  5. d2d4  5... g8f6 