What are exactly the most significant co-morbidities that heighten the risk of dying from COVID-19?

Breaking down the Covid-19 risk with the most common co-morbidities, the scientists found that cancer raises the risk 3.5-fold, chronic obstructive pulmonary disease (COPD) 2.6-fold, and diabetes and hypertension by about 60%. Because it isn’t unusual for someone to have an underlying disease (especially diabetes and hypertension) but not know it, the last figure is likely an underestimate.

China CDC’s analysis of 44,672 patients found that the fatality rate in patients who reported no other health conditions was 0.9%. It was 10.5% for those with cardiovascular disease, 7.3% for those with diabetes, 6.3% for people with chronic respiratory diseases such as COPD, 6.0% for people with hypertension, and 5.6% for those with cancer.

Source: https://www.statnews.com/2020/03/03/who-is-getting-sick-and-how-sick-a-breakdown-of-coronavirus-risk-by-demographic-factors/