Qualia is the term people often use to mean "what it's like". The hard problem is "why is there qualia". This of course assumes that qualia exists as a coherent thing, which some philosophers dispute.
This reduces to the intractable mystery of existence. A more interesting question would be, as usual "how".
There are serious attempts at this, coming from both neuroscience and physics (e.g. for the latter https://pubs.aip.org/aip/adv/article/15/11/115319/3372193/Un... )