It is irrelevant whether consciousness is an "illusion." The hard problem of consciousness is why there's any conscious experience at all. The existence of the illusion, if that's what you choose to label it, is still equally as inexplicable.
Of course science may one day be able to solve the hard problem. But at this point in time, it's basically inconceivable that any methodology from any field could produce meaningful results.
One thing scientists are trying is to see what interventions in the brain seem to make consciousness go away. Continued work in that vein may well set bounds on how consciousness can and cannot be caused and give us some idea.