This is a rough implementation of local multiplayer (hotseat). Everything works smoothly except in age transitions only the first player gets to choose their civilization (everyone else gets auto-assigned).
Steam workshop isn't up yet, so you'll need to extract the mod to your "{user}\AppData\Local\Firaxis Games\Sid Meier's Civilization VII\Mods" folder and enable by navigating to Additional Content -> Mods in the main menu and enabling "Hotseat".
https://forums.civfanatics.com/resources/hotseat.31913/
Steam workshop isn't up yet, so you'll need to extract the mod to your "{user}\AppData\Local\Firaxis Games\Sid Meier's Civilization VII\Mods" folder and enable by navigating to Additional Content -> Mods in the main menu and enabling "Hotseat".
https://forums.civfanatics.com/resources/hotseat.31913/