Please, any recommendations to visit in Cairo?
Definitely also the Citadel.
I suggest that you read a guide book and see what appeals to you as how you choose to spend your time depends very much on your interests - which you have not mentioned.
I did a lot of background reading before my first visit to Egypt and, with only 3 whole days in Cairo that occasion, I spent one at Saqqara after a brief detour to Memphis, one at the Antiquities Museum and one at the Giza Pyramids and Solar Boat museum there.
You could easily spend a few days in Cairo because there is a lot inside and just outside the city.
Downtown Cario: Islamic and Coptic Cairo are musts. You can learn details here.
Egyptian Museum is incredible. This guide will ensure you see everything you should
Saqqara and Dahshur: Egypt's oldest pyramids
Giza Pyramid Complex: The world's most famous and tallest pyramids.