A Research Study to See How Much CagriSema Lowers Blood Sugar and Body Weight Compared to Tirzepatide in People With Type 2 Diabetes Treated With Metformin With or Without an SGLT2 Inhibitor

This study will look at how well CagriSema helps people with type 2 diabetes lower their blood sugar and body weight. CagriSema is a new investigational medicine. Doctors may not yet prescribe CagriSema. CagriSema will be compared to a medicine called tirzepatide that doctors may prescribe in some countries. Participants will get either CagriSema or tirzepatide. Which treatment participant get is decided by chance like flipping a coin. Participant will have an equal chance of receiving either drug. For each participant, the study will last for up to one and a half years.

Inclusion Criteria: * Male or female (sex at birth). * Age 18 years or above at the time of signing the informed consent. * Diagnosed with type 2 diabetes ≥ 180 days before screening. * Stable daily dose(s) ≥ 90 days before screening of any of the following antidiabetic drug(s) or combination regimen(s) at effective or maximum tolerated dose as judged by the investigator: metformin with or without an sodium-glucose co-transporter-2 (SGLT2) inhibitor. * HbA1c 7.0-10.5% (53-91 mmol/mol) (both inclusive) as determined by central laboratory at screening. * Body mass index (BMI) of ≥ 30.0 kilogram per square meter (kg/m\^2) at screening. BMI will be calculated in the electronic case report form (eCRF) based on height and body weight at screening. Exclusion Criteria: * Female who is pregnant, breast-feeding or intends to become pregnant or is of childbearing potential and not using a highly effective contraceptive method. * Renal impairment with estimated Glomerular Filtration Rate \< 30 milliliter per minute per 1.73 square meter (mL/min/1.73 m\^2) as determined by central laboratory at screening. * Treatment with any medication for the indication of diabetes or obesity other than stated in the inclusion criteria within 90 days before screening. However, short term insulin treatment for a maximum of 14 consecutive days and prior insulin treatment for gestational diabetes are allowed. * Uncontrolled and potentially unstable diabetic retinopathy or maculopathy. Verified by an eye examination performed within 90 days before screening or in the period between screening and randomisation. Pharmacological pupil-dilation is a requirement unless using a digital fundus photography camera specified for non-dilated examination.