Tremelimumab is a new type of drug for various types of cancers. It works in a similar way to durvalumab and may improve the effect of durvalumab. This may also help slow the growth of the cancer cells or may cause cancer cells to die. Tremelimumab has been shown to shrink tumours in animals and has been studied in nearly 1500 people and seems promising but it is not clear if it can offer better results than standard treatment alone when used with durvalumab