I saw this a few days ago – Gene Editing Must Reckon With the Unforeseen (There are no superior genes. Rather, every version of a gene comes with tradeoffs.): https://getpocket.com/explore/item/gene-editing-must-reckon-with-the-unforeseen
The below best sums it up.
But what often goes unacknowledged is that there are no superior genes. Rather every version of a gene comes with tradeoffs. So gene modification should make us cautious: It may, depending on our environmental niche, impose a new weakness or the loss of a strength we can’t foresee.
All one has to do is read or watch some of the best and worst science fiction books and movies to see how badly this can turn out. The bad thing is what seems to be a minor change may not show a downside until much later in a generation or two. Or, it could show up right away or shortly after the change is made. Will the change be reversible? Honestly, there is no way to know. Plus, how the change affects animals does not mean it will affect humans in the same way.