Florentino Pérez said they plan to sign Mbappe for the next season. But considering the current situation of Mbappe, I assume Pérez may try to sign him now. Moreover, Real Madrid still has no a top striker, they only signed Joselu. I think Joselu isn't enough to compete for UCL title.
Indeed, after the departure of Benzema, they still do not have a replacement that is at least equal. And with Mbappe, this would be an extraordinary thing, but it's still wishful thinking at this time, because it's still just rumours.