By late antiquity, the cult of Isis was by far the most prominent Egyptian derived religious movement (although it was very Hellenized). It spread throughout the Roman Empire, but declined as Christianity became dominant.

The last known operational temple of Isis was on the isle of Philae in the Nile. It remained open all the way until the 6th century, when Justinian suppressed it. The cult of Isis never officially coexisted with Islam, which was invented about a century after the closing of Philae. Perhaps some farmers were still practicing in secret, but I've never seen any evidence this is true.

It did significantly influence Christianity. The modern depiction of Mary and baby Jesus owes quite a bit to Isis and her son Horus. Trinitarianism also owes quite a bit to Egyptian religion, although many Eastern cults were Trinitarian.