Cashmere is one of the rarest fibres in the world, combed from the undercoat of Chinese and Mongolian goats. Because it is soft and fuzzy, cashmere can be prone to pilling, caused by rubbing during regular use. This is perfectly normal, and pilling can preferably be removed with a sweater comb.
Always check the instructions on the care label first and wash cashmere by hand or in cold water on the delicate cycle in the washing machine, using a mild detergent. Put cashmere in a mesh washing bag to protect it from snagging. Dry flat on a towel.