If you watch the video carefully you’ll see that the Nintendo Switch has two controllers built into the sides for multiplayer gaming anywhere!
Gaming springs into action by removing detachable Joy-Con controllers from either side of Nintendo Switch. One player can use a Joy-Con controller in each hand; two players can each take one; or multiple Joy-Con can be employed by numerous people for a variety of gameplay options. They can easily click back into place or be slipped into a Joy-Con Grip accessory, mirroring a more traditional controller. Or, if preferred, the gamer can select an optional Nintendo Switch Pro Controller to use instead of the Joy-Con controllers. Furthermore, it is possible for numerous people to bring their Nintendo Switch systems together to enjoy local multiplayer face-to-face competition.
https://youtu.be/f5uik5fgIaI?t=103