<MenuItem Text="MyMenuItem" Command="{Binding SwitchMode}">
    <Shell.MenuItemTemplate>
        <DataTemplate>
            <StackLayout Orientation="Horizontal" HorizontalOptions="Center">
                <Label Text="{Binding Text}"/>
                <Switch IsToggled="{Binding IsModeActivated}"/>
            </StackLayout>
        </DataTemplate>
    </Shell.MenuItemTemplate>