Typically, a combobox has one item. But you can set it to have a datatemplate.
something like
<ComboBox Height="23" HorizontalAlignment="Left" Name="comboBox1" VerticalAlignment="Top" Width="120" >
<DataTemplate>
<StackPanel Orientation="Horizontal">
<TextBlock Name="test1" Text="{Binding something}"></TextBlock>
<TextBlock Name="test2" Text="{Binding somethingElse}"></TextBlock>
</StackPanel>
</DataTemplate>
</ComboBox>