This is a Phase I, open-label, multicenter study of continuous oral dosing of AZD4635 administered as a single agent and then in combination with a PD-L1 antibody, durvalumab. The study design allows an escalation of dose with intensive safety monitoring to ensure the safety of the patients. The primary objective of the study is to determine the maximum tolerated dose of AZD4635 in combination with durvalumab.