People in this study will get two medicines through an IV: pembrolizumab (about 30 minutes) and ADU 1805 (about 1.5 hours). Treatments happen every 3 weeks and can last up to 2 years, with safety checks for about 4 more months. At first, there are extra visits, then visits every 3 weeks with an extra one every 9 weeks. Scans like CT or MRI will be done every 8 weeks to see how tumors respond. Some people will need tissue samples called biopsies before and after treatment, depending on their cancer type.

This study is for adults who have serious cancers called advanced solid tumors. These include certain types of cancer such as colorectal cancer, endometrial cancer, kidney cancer, and lung cancer.

People can join this study if they have one of these serious cancers: colorectal cancer, endometrial cancer, kidney cancer, or lung cancer. They must be adults who can come to all visits for screening, treatment, and follow-up. Women cannot be pregnant or breastfeeding and must take pregnancy tests and use birth control as the study requires. Everyone must agree not to take certain medicines or treatments, such as other cancer drugs, radiation, some steroids, or live vaccines. They also cannot join another study for at least 28 days before starting and during this study.

This study is testing a new medicine called ADU 1805 to learn if it is safe and how it works in the body. In one part of the study, ADU 1805 is given with another medicine called pembrolizumab (KEYTRUDA®) to people who have certain serious cancers. The goal is to see how their cancer reacts and to check safety.