Ruy López
Are you asking for the best move after 1.e4 e5 2.Nf3 Nc6 3.Bb5?
Probably 3...Nf6. The Berlin has caused many to abandon the Ruy at the top level. I cannot speak from a lot of experience though. I play the Petroff and French as Black, and 1.b4, 1.c4, or 1.d4 as White.
1. e4 e5 2. Nf3 Nc6 3. Bb5 a6
This is by far the most popular response and a solid choice at all levels. The idea behind 3... a6 is to challenge White's bishop, forcing it to either exchange on c6 (which doubles Black’s pawns) or retreat. If White exchanges, Black gets a slight advantage in the pawn structure and can continue development comfortably.
After 4. Ba4 (the bishop retreats), Black can continue with Nf6 and Be7, aiming to control the center with moves like ...d5 or ...c5. It's solid and flexible, leading to a long-term strategic battle.