I wanted to ask is there a possibility to have an ignore file for specific files on XCode 26 like all of the other AI IDE's have?
It's somewhat impossible to use the feature without this type of functionality on the platform.
If not possible, will it be available sometime in the future?
The intelligence features in Xcode have a feature for exactly this starting in Xcode 26!
To ask the context search tools to avoid specific files or parts of your project, you can put a file called .contextignore next to the workspace or project file for your project and use .gitignore-style syntax to describe "globs" to match relative paths against.
This should work in a very similar way to how other, similar code editing environments with intelligence features support ignoring files.