I think both variables are wrong.
First, get the current slug.
you can do this with
Next get the current collection
not the entire CMS Data variable.
Each collection outputs a variable by default called Collection Item. This represent the curernt iteration. So if you bind something to collection that has three posts, the Collection Item variable will be the first post on the first box, the second post on the second box etc.
So you need to do something like
Collection Item.data.slug
I don't know the exact data structure so just use autocomplete to access it.