When creating a View, you may be interested in filtering that View by a column with multiple values. For example, say a project can have more than one lead, and you want to see any instance in which someone in the Lead column is mentioned in a View of that Table.
To do so, you would use the CONTAINS formula to find a value in the column. Here's what that looks like:
You can see a version of this in the GIF below. You'll see there are two Views, "Project," and "Leads". The Leads column is setup to be a linked column allowing multiple values (so called "multiselect" column). We then filter this view to only show rows where Alan is one of the leads: