It can.
Your cover is often one of the first things a reader notices. A professional cover that clearly communicates the book's genre and tone can make it easier for the right readers to recognize that the book may interest them.
A cover that is difficult to read, looks dated, or sends the wrong genre signal may reduce reader interest even when the book itself is a good fit.
The cover is not the only factor affecting promotion results, but it is an important part of the decision readers make before clicking.