Hello @cesarholavr, welcome to the forums.
This subject has been discussed in this post: Use Passthrough with ZED mini with chroma keying
And possibly other that I don’t recall. The short answer is that there is no way to do it out-of-the-box with the existing shaders.
We can try helping you with the projectif you have questions on the ZED SDK/Unity integration, but we won’t be developing this feature ourselves in the near future.