If truly working within the agile philosophy, as there is no Agiletm process, then look at the first value: Individuals and interactions over processes and tools.
The tools are there for the people. How does this field, and others, best make sense for your context?
The original intent of a user story was for recording the general idea. As its use has grown over the years, so has its information bloat. It is important for a product team to understand the intended value and potential risk, so many tools have added fields for these values. Much like the Severity and Priority fields for bugs, one's specific context should drive their meanings.
Most of these fields are independent: Microsoft Docs 1 2
A subjective rating of the relative uncertainty around the successful completion of a user story.
Defined allowed values are:
1 - High
2 - Medium
3 - Low