Matt Allington shows how you can build a dual-axis line chart in Power BI:
Unfortunately, Power BI does not support a dual axis line chart as a standard visual at this time. The good news however is there is a custom visual called “Multiple Axes chart by xViz” that can do this in Power BI. This visual has been around for a while, but there have been some formatting issues (in my view) that prevented it being a solution to this problem – that is now fixed). I will demonstrate how to set up a dual axis charge using the Adventure Works database and this visual.
Honestly, I’m pretty happy that Power BI does not support a dual-axis line chart. It is the cause of so many instances of spurious correlation that I’d err on the side of not including multiple axes.