I have created a character using headshot in CC then sent it to iClone for facial mocap.
What I'd like to do is make it look like a cartoon, so I turned to "Toon Shader".
But it doesn't really make it look like a cartoon at all.
Is there any settings that I should know to make it happen?
Or is not possible for the Toon Shader to make a character into a cartoon character?
If it's not possible, can I make it look like a cartoon without using the Toon Shader?
I remember seeing a post where some other methods are preferred over the Toon Shader, but I can't seem to find the post.
Please help.

Have you tried? 
https://magazine.artstation.com/2020/06/fast-cartoon-design-with-character-creator-3/
or 
https://magazine.reallusion.com/2020/06/24/master-class-1-fast-cartoon-design-with-character-creator/?utm_source=luis_article&utm_medium=influencer&utm_campaign=outbound&utm_term=2020_1_A

Thanks but that's not an option, because what I want to do is make a "cartoonish" character out of the real human character made with the headshot plug-in from a real human picture. 

I think your best (least work intensive) option would be to take the photographs you are using to create your "real" human first into illustrator and there work on the images to make them look like a cartoon character and THEN apply them to the 3D model.  If you first apply the photographic textures and then want to go to cartoon look you'd essentially have to use a process that's nearly identical to the the process of turning live action footage into cartoons.  It's possible but there is not a single tool that's doing a good job with it out there.  A Scanner Darkly went through Illustrator frame by frame to do it.  A recent music video went frame by frame through  Prisma on a tablet to do it.  Undone was first shot and then animated over the photo.  All of this is very labor intensive.

Thanks. So the Toon Shader in iClone isn't supposed to make a character look like a cartoon at all?

I have not used it but from what I have seen it's essentially reducing the bit depth from a few million colors. to a few colors.  Illustrator will do something similar but you'll have a lot more control.  Now Reallusion isn't going to like reading this but when I want a CG character to look like a drawing I go to Poser.  Poser actually has some nice "art" presets that can be tweaked and some of those do look quite good.  I don't think it's possible to export them as shaders though.  I think it's a built in post process that only effects the render.  Depending on what it is you want to do it may be possible to create an iClone to Poser workflow.  I am putting a file bellow of a story board page that I did using Poser to illustrate what I mean.  The next question is then of course if you also want the features of your character to be more cartoonish?  If so you should be able to alter the features in CC to resemble more of a caricature of your character.  In the end the combination of the two should enable you to have a recognizable character that does look like a cartoon.
Hope this helps

I think that you have to specify what you mean by cartoon character, as there are many possible styles. 

The problem with the cartoon shader in iClone is that it insists on using only one light, so it is kind of limited. But I have created a comic with it.

For a more recent project I took regular renders from iClone and then made modifications in my graphics editor (Paint Shop Pro). Assembled in panels using Comic Life.



This is not the final version as the characters are are being updated in CC3.3.

EDIT: Fixed typos...

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To add to this, you also may need to prepare the texturing of your characters. Toon characters are shaded "flatter" then more realistic looking ones. One simple way to do that is to use self-illumination on the skin.

We used to have a member years ago who was a master in getting a toon look, way before the built-in Toon Shader.

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The Toon Shader only gets you so far, and frankly, the less, the better--especially the outlines. Check out the toon-style Base Map for Walt's face. Fred's face texture is halfway between toon and realistic. Set your self-illumination high. Make all your textures simple, flat-colored. Count on tweaking any video you generate.



Animating now to life itself --Walt Whitman 

@hicksight: thanks, that's what/who I meant.

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