There are lots of examples. Phonemes for language and are a very common example of things that can't be learned easily or at all later in life.

But huge changes like a major color might overcome that. Humans learn to recognize new major objects they've never seen before.

Humans can learn to recognise new sensory modalities, too (see paragraph 4 of doi:10.3389/fnhum.2019.00443's introduction) – but only if there's hardware that responds to them. The question is whether the visual cortex is capable of making the distinctions.

If colourblindness glasses (e.g. EnChroma®) work for you, then I suppose the answer is trivially "yes, because it already does" – and we should expect gene therapy to be useful. If there are people for whom those glasses don't do anything at all, I'd be more cautious.