A Research Study Looking at How Well a Combination of the Medicines Semaglutide and NNC0480-0389 Works in People With Type 2 Diabetes

This study is looking at semaglutide in combination with a potential new medicine (NNC0480-0389) in people with type 2 diabetes. The study is being conducted to see how well semaglutide, in combination with different doses of NNC0480-0389, work to lower blood sugar levels. Results from this study will be used to select the doses of the two medicines for other studies. Participants will either get: Semaglutide (a medicine doctors can already prescribe for treatment of type 2 diabetes) in combination with NNC0480-0389 (a potential new medicine) or placebo (a 'dummy' medicine that looks like the medicines but without any medicine). NNC0480-0389 alone, or semaglutide alone which treatment participant get is decided by chance. Participant will need to take 2-3 injections once every week during the study. One injection will be with semaglutide or placebo and 1-2 injections will be with NNC0480-0389 or placebo. Participant must inject the study medicines themself into the stomach, thigh, or upper arm. The study will last for about 41weeks. Participant will have 20 clinic visits. Participant will have blood samples taken at all clinic visits. At 3 clinic visits, participant will also have an electrocardiogram (ECG). This is a test to check participants heart. Participant will have their eyes checked before or at the start of the study and at the end of the study. Women can only take part in the study if they are not able to become pregnant