https://www.gamespot.com/articles/pokemon-lets-go-trailer-shows-off-mega-evolutions-/1100-6461057/

The Pokemon Company has shared a new English trailer for Pokemon: Let's Go, Pikachu and Let's Go, Eevee. This one focuses primarily on Mega Evolutions--which we recently learned would be returning in the upcoming games--as well as a few more familiar characters and places players will encounter on their journey across the Kanto region.

The trailer begins with a tour of Vermilion City, the home of the Electric-type Gym Leader, Lt. Surge. Just as in the original Pokemon Yellow version, Lt. Surge battles alongside a Raichu, but players must first solve a puzzle in his Gym before getting the opportunity to challenge him. The trailer also provides a quick glimpse of the S.S. Anne, the luxury cruise liner docked at Vermilion harbor at the time players first arrive in the city.