I ask this because Thor for example is in the Thor collection, but it also has a Keyword of “Marvel Cinematic Universe” so at the moment I would have to create a second Collection and add all the films in manually to be able to see which films I have and do not have. If the TMDB Keywords are imported and there is a way to search for them or filter on them, then I would be able to find all MCU films in one go, without having to do any leg work keeping my database up to date manually, which is a bit pointless if the data already exists in another system.
If you switch to TheMovieDatabase as your primary agent and tick the check box ‘Use collection info from The Movie Database’ you should get them.
(ignore the red marker in this screen shot)

But beware: there are a lot of wacky collections on TMDB!
I already have that on, my point is that Thor on TMDB is only in a collection of Thor and not MCU, but it does have a Keyword of MCU in TMDB. Same for Captain America etc.
I was going to create a new feature suggestion to import “keywords” as a new category under tags, when I found this older similar request. I didn’t realize the “use collection info from TheMovieDB” in settings may do that.
However, I’d suggest that there is still a use for importing keywords separately from “collections”. I use collections to relate similar related movies and “bundled” dvd sets (like a 50 movie pack). If what you’ve said means that all of a sudden there would be dozens of “collections” created from the keywords section of TheMovieDB, I would dislike having those all mixed with my own created collections, especially because of the “wacky collections” problem you mentioned. I was hoping to have it filterable just like “Genre”, “Actor”, “Director”… Again, the unrestricted format for keywords on that site would probably end up with a very large filter list, but it’s no worse than filtering by “Actor” is now.
It would be nice to ask plex to return a list of “Easter”, “Christmas”, “Romance”, … based on keywords that others have taken the time to associate with movies.
This feature request is far more important than people realise
Specifically warning about/ filtering out: end user trauma. Unfortunatley sexual violence is far to common in media and reality. Having TMDB and [feature requested at TVDB] being scraped from the databases, and shown on the tv/movie page with it being clickable to filter the libary. Aditonally have the tags disableable in settings. Also using this to create a default filter instead of a libary sharing filter. This gives them warning but does not filter everything out. there are alot of good shows and movies that wont be there (for example westworld). The main problem is remembering every scene in every show and every movie to tag it with a content warning.
aside from that it would be realy nice to filter libary with sub generes like steam punk, or league of legends tag for arcane and its future reboot
If you use one of the modern plex clients, you should see a description by CommonSenseMedia.org on many titles.
It’s not a full replacement for the original request, but can help out in many cases.
Plex does support the assignment of more than one genre to any item. If the metadata source provides them, Plex can use them.
That kind of thing is probably better managed by the use of collections.