This study looks at how a new medicine insulin icodec helps in reducing blood sugar levels when given along with semaglutide in patients with type 2 diabetes. Participants will get the medicine insulin icodec once a week in the first part of the study (run-in period-26 weeks). Participants will only enter the second part of the study if the blood sugar levels have not reduced to normal. If blood sugar levels are normal after the first 26 weeks, participants will continue in a 5-week follow up period. In the second part of the study (intensification period-26 weeks), participants will get both insulin icodec and semaglutide once weekly after which they will continue in a 5-week follow up period. Participants will have to inject the study medicines once a week on the same day of the week in a skin fold in the thigh, upper arm or stomach. The study will last for about 13 months. Participants will get a blood glucose meter to check blood sugar levels. In addition, participants will be asked to enter blood sugar levels in the study phone. In addition, Participants will be asked to enter selected few blood sugar values (three times during the study) in a paper diary that will be provided to participants. Women cannot take part if pregnant, breast-feeding or plan to get pregnant during the study period.