Bar charts and line graphs can be combined. Climate graphs are an example of this. The x-axis shows the months of the year and there are two y-axes to show average temperature and total rainfall.

You can also change the chart type for one series (for example, make it a line graph instead of a bar graph). With the series selected, click the Design tab, go to the Type group, click Change ...

Bar charts and line graphs can be combined. Climate graphs are an example of this. The x-axis shows the months of the year and there are two y-axes to show average temperature and total rainfall.