The Trending toggle provides you to view the data trend of the inputs that you provide in your query. This toggle is only available for the Count and Ratio function type of the Numerical widget. You can view the Trending data of a single query or multiple queries.

Trending data for multiple queries

The Trendline Color Mapping section allows you to change the color of the trendline. Click on the displayed color to view the options from the Color Picker

Trending colour change