I'm trying to import a Daz character into CC3 with the tan lines.  The tan lines say iray and don't show up in character creator.  I'm not really sure how they get applied or how to preserve them.  
Is there a way to do this?  Or a tutorial somewhere?

The tan line file is basically a picture of the body that has everything blacked out except where the whiter skin should be. 
I'm not sure where to apply it of I loaded it into CC3.  I fooled around a bit and had it on the figure but the body skin ended up being darker then the legs and arms and the chest area was out of alignment probably due to the body morphs I exported with. 

If you have a texture like you describe (black except for the tan lines), then you can load that in the Blend channel of the body textures and set the Blend Mode to Add. Use the Strength slider to adjust the contribution.

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He can't do that, Job -- you can't just load in textures to a Daz imported character into CC3 (it needs to be remapped).

OP -- tell me exactly what Daz character you are trying to load and I'll tell you how to do it.

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Alienware Aurora R16, Win 11, i9-149000KF, 3.20GHz CPU, 64GB RAM, RTX 4090 (24GB), Samsung 870 Pro 8TB, Gen3 MVNe M-2 SSD, 4TBx2, 39" Alienware Widescreen Monitor
Mike "ex-genius" Kelley

It's a genesis 8 character. I load it in Daz and play with the dials and then apply the tan lines which are for a different genesis 8 character.  Everything looks good in the Daz render. 
Ideally I'd like to be able to save the tan lines and apply then to any character. Or at least any genesis 8 character.  If that's possible. 

Yes, but you need to tell me *exactly* what characters you are trying with what (links to the Daz product page would be useful).

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Alienware Aurora R16, Win 11, i9-149000KF, 3.20GHz CPU, 64GB RAM, RTX 4090 (24GB), Samsung 870 Pro 8TB, Gen3 MVNe M-2 SSD, 4TBx2, 39" Alienware Widescreen Monitor
Mike "ex-genius" Kelley

I have this character 
https://www.daz3d.com/taryn-hd-for-genesis-8-female

I apply the dark tan line file from this character https://www.daz3d.com/dayton-bundle-for-genesis-8-females

Basically I've been trying to import a few of my Daz characters and save them out and was trying to add the tan lines with them. 

It's a little complicated, but here are two ways of doing it:

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Alienware Aurora R16, Win 11, i9-149000KF, 3.20GHz CPU, 64GB RAM, RTX 4090 (24GB), Samsung 870 Pro 8TB, Gen3 MVNe M-2 SSD, 4TBx2, 39" Alienware Widescreen Monitor
Mike "ex-genius" Kelley

Cool thanks. I should be able to get it working now.