Although the game is digital, physical "Collector's Packs" were released in 2009. These are now rare collector's items rather than functional game installers: : You can find original physical copies, such as the League of Legends (PC, 2009) Go to product viewer dialog for this item.
While you don't buy the game itself, you can purchase "Riot Points" (RP) to unlock champions, skins, and boosts: where to buy league of legends
You can download League of Legends for Windows and macOS directly from official digital storefronts: Although the game is digital, physical "Collector's Packs"
League of Legends - Free download and play on Windows | Microsoft Store. Microsoft Store Shop - League of Legends Wiki | Fandom Although the game is digital