The Steam Deck is a handheld gaming computer produced by Valve Corporation, designed to run a portion of games available on the Steam storefront client. Built upon the experiences gained from Valve's earlier ventures with Steam Machine and the Steam Controller, the Steam Deck integrates a custom AMD APU and SteamOS, a Linux-based operating system. The Steam Deck represents Valve's pivot towards a fully in-house hardware development approach, following the challenges faced with Steam Machines' reliance on OEMs and the requirement for native Linux game support.
https://en.wikipedia.org/wiki/Steam_Deck