CGK linens set is from Microfiber
It offers several advantages, including durability, softness, and resistance to wrinkles and shrinking. They are also typically more affordable than other types of sheets and tend to dry quickly, making them convenient for busy households. Additionally, microfiber sheets are often hypoallergenic, making them a great choice for those with allergies or sensitive skin.

But I personally prefer more natural material for linens as cotton or so.