On the iOS version of Microsoft To-Do, the padding between the headline block and the task list is almost nonexistent. The padding should be increased to be consistent with the Windows and Mac version of Microsoft To Do. As a graphic designer it makes me want to scrape my eyes out of my skull.
You should also consider increasing the spacing between items a bit across all platforms, it's a very thin space on smaller displays, and it just doesn't seem very clean.
This is how it looks on iOS.
This is how it looks on Windows.