Filters in Google Data Studio work in much the same way as in Google Analytics, by retrieving records that match (or if you prefer, don't match) certain conditions. As Data Studio Help says:
Filter properties (or just filters, for short) refine or reduce the data shown to report viewers. This lets you focus on the data that best communicates the story you want to tell, making your reports more relevant to your audience.
You can apply a filter to a chart, control, page, or the entire report using the DATA properties tab.
But if you apply a filter to a table, it will filter all the data in that table. What if you only want the filter to apply to one particular column?
For example, I recently wanted to display a table with a column showing the Total Events metric for one particular Event Action. However I didn't want the other columns in the table to be filtered in this way.
The solution, somewhat unintuitively in my opinion, is to use Google Data Studio's data blending functionality. Effectively, you will end up with one table using two different data sources (or rather, the same data source twice - once with the filter applied, and once without).
Here's my quick how-to. I'm focusing on the problem at hand rather than the mechanics of creating a table or a filter as I assume you already know how to do that.
If you click on this new table, you will see it has the 'Data source' of Blended Data. Edit that data source, and you will see your two component data sources - the unfiltered and the filtered data. You can then make further changes, such as adding Metrics to either of these, if you wish.
It's also worth noting that you can blend a maximum of five data sources in one chart, so this does put a limit on the number of individually filtered columns you can have in the one table. But quite a generous one!
Here's a short video from Google about this Data Studio feature: