Add a secondary axis in a chart in Excel

When the numbers in a chart vary widely from data series to data series, or when you have mixed types of data (price and volume), plot one or more data series on a secondary vertical (value) axis. The scale of the secondary vertical axis shows the values for the associated data series. A secondary axis works well in a chart that shows a combination of column and line charts. You can quickly show a chart like this by changing your chart to a combo chart.

Select a chart to open Chart Tools.

Chart Tools
Select Design > Change Chart Type.

Change Chart Type
Select Combo > Cluster Column - Line on Secondary Axis.

Cluster Column
Select Secondary Axis for the data series you want to show.

Secondary Axis
Select the drop-down arrow and choose Line, then click OK.

Line Option