The purpose of the study is to determine a subcutaneous (SC: under the skin) durvalumab + recombinant human hyaluronidase (rHu) dose that yields systemic drug exposure similar to intravenous (IV: into the veins) durvalumab administration and to evaluate the pharmacokinetics and safety of SC durvalumab + rHu injection in participants with different types of solid tumours (cancers).