Death Data is discoverable in SimplyAnalytics.
Use the blue menu on the left of this screen to navigate to the SimplyAnalytics page, then the subpage on "Add Data to Your Project."
When looking for death data, select the Health option and then select the Deaths category in the middle menu that will appear.
You can then select whatever death data is important to your project. For example, you can add deaths from all causes (this will give you the total of deaths that took place in your census tract or county for the most recent year of data) or you can add deaths from a specific disease or incident to your project.