Answering your question https://support.microsoft.com/en-us/office/highlight-patterns-and-trends-with-conditional-formatting-eea152f5-2a7d-4c1a-a2da-c5f893adb621
But I assume you want to something in Mendix.
I guess you use the datagrid to display a list and you want to format a cell based on a value. This isn't possible in a datagrid. Use the Datagrid 2 instead and use dynamic classes to set background color based on value.