Arcade expression for combining data sources

[christg]

Hello

I have 2 large files containing the same types of data. I'd like to combine them in arcgis online in order to use them as data sources for dashboard indicators.
But I don't know how to write the arcade code.
Can anyone help me?

[KenBuja]

There is a GitHub repository of many Arcade expressions. This one shows how to combine multiple layers for use in a Dashboard