Well, this is what we know of the loot filter thus far;
Sarno on April 11, 2020:
Source: Discord
Sarno on May 21, 2020:
Source: Discord
Mike Weicker on July 10, 2020:
With regards to the loot filter. It’s going to be very unique because our crafting system means that you’ll be wanting to filter items by very different criteria than those other games.
The interface will be more similar to GD in that it’s in game. You’ll be able to do things like save multiple filter profiles.
The current plan is to make a list of rules like “show all items with a fire damage affix” or hide all items with less than 5 total tiers" if a one tier fire damage item drops, it will show up if the first one is higher but will be hidden if the second one is higher.
This isn’t created yet so it could dramatically change.
Source: Discord
If it does turn out to be anything like Grim Dawn's loot filter it's going to be pretty robust and easy to use. It was also added fairly recently, like within the past 6 months or so (or maybe longer as time flies).