61 Chapter 597 (p. 9-19) and Episode 516, Rayleigh takes Luffy to Rusukaina to train him.

What episode does Luffy train with Rayleigh?

"Luffy's Training Commences - 2 Years From Now at the Promised Place" is the 516th episode of the One Piece anime.

In which episode Luffy learns Haki?

For the anime, Luffy finally learned Haki in Episode 517, which showed the end of Luffy's training. He then demonstrated Conqueror's Haki in Episode 518 to collapse Demalo Black, Luffy's impostor, without affecting the others around them.