Cypher is one of the strongest agents on Sunset. He is able to hold down A, B and mid very well with his utility.
Strong counter agents for Cypher are Raze, Sova, and Kay/o. Their utilities are able to break Cypher's trips, making it easier to enter a site.
Enemies will rush through mid and can push your spawn fast if no one is holding top mid. Be careful for the late round lurks as well.
When rotating between A and B, make sure to have your crosshair ready when crossing past mid.
It's best to 3-2 split A main to take site. Avoid pushing only one spot. But on B site, you do not need to split as often.