Keeping the queens on the board is also possible, but it doesn't guarantee White any special advantage.
1. e2e4  1... c7c5  2. g1f3  2... d7d6  3. d2d4  3... c5d4  4. f3d4  4... g8f6  5. b1c3  5... a7a6  6. f2f3  6... e7e5  7. d4b3  7... c8e6  8. c1e3  8... f8e7  9. d1d2  9... h7h5 When I was a child, I studied the Najdorf Defense to the point that I almost memorized the fantastic book \"The Najdorf for the Tournament Player\" by John Nunn. Back then, this type of move, moving a pawn on the side that your opponent is going to attack, was unthinkable. But chess strategy advances and each generation learns something new. The move h7-h5 has become one of Black's main options against the English Attack and the idea was even carried over to other variations of the Sicilian Defense. 10. c3d5  10... f6d5  11. e4d5  11... e6f5  12. f1e2  12... a6a5 It's not a very pretty move, but this is part of the Najdorf players' arsenal, played in several similar positions. 13. a2a4  13... e7h4  14. g2g3  14... h4e7 This position has been tested in many correspondence games. The idea of inserting a5-a4 is, I imagine, to prevent the white knight jumping to a5. 15. e2b5  15... f5d7  16. d2e2  16... e8g8  17. b3d2 [%c_effect d2;square;d2;type;GreatFind;persistent;true] An important move to reposition the knight at the best moment. 17... d7b5  18. e2b5  18... e7g5  19. e3g5  19... d8g5  20. e1c1  20... f8c8  21. c1b1 When in doubt, play Kb1. 21... b8a6 A new move. It's redundant to say that Caruana is well-prepared. 22. d2e4  22... g5d8  23. f3f4  23... a6c5  24. h1e1  24... c5e4  25. e1e4  25... f7f5 [%c_effect f5;square;f5;type;GreatFind;persistent;true] 26. e4e3  26... e5e4 The last moves from both sides were very logical. 27. b5e2  27... d8d7 [%c_effect d7;square;d7;type;GreatFind;persistent;true] A very accurate move and the only one to equalize. Black should not passively defend the h5-pawn. 28. e2h5  28... d7a4  29. d1d2  29... c8f8 [%c_effect f8;square;f8;type;Inaccuracy;persistent;true] This is inaccurate. 30. g3g4 [%c_effect g4;square;g4;type;GreatFind;persistent;true] 30... a4e8  31. h5g5  31... e8d8  32. g5h5  32... d8e8  33. h5h3  33... e8g6  34. d2g2  34... g6h7 