"Keep the current script, but add onto it by making it so it saves the the team name as well as the team color. And when the player rejoin the game it should put them back into whatever team they were in when they left."

-- server script 
local DataStoreService = game:GetService("DataStoreService")
local myDataStore = DataStoreService:GetDataStore("PlayerTeamData")

game.Players.PlayerAdded:Connect(function(player)
    local savedData
    local success, err = pcall(function()
        savedData = myDataStore:GetAsync(tostring(player.UserId))
    end)
    if success then
        if savedData then
            local teamColor = BrickColor.new(savedData.teamColor)
            local team = Instance.new("Team")
            team.TeamColor = teamColor
            team.Name = savedData.teamName
            team.Parent = game:GetService("Teams")
            player.TeamColor = teamColor
        end
    else
        warn("Failed to load data: "..err)
    end
end)

game.Players.PlayerRemoving:Connect(function(player)
    local success, err = pcall(function()
        myDataStore:SetAsync(tostring(player.UserId), {teamColor = tostring(player.TeamColor), teamName = player.Team.Name})
    end)
    if not success then
        warn("Failed to save data: "..err)
    end
end)