Is this a display state or an interactive control?
Your current thought seems to be trying to either:
- Add another state to a checkbox (highly unconventional)
- Or, use a checkmark icon to describe a status
We don't have much details of your use case, but if you wish to have users interact and change status on a record, you could use a dropdown:
An example from Airtable:

On click for any cell in the column:

In this case, the lozenge is actually in a table cell with a dropdown, and color coding differentiates the status.
This way you have a clear, readable label, no icon interpretation necessary: icons without labels can be notorious for ux problems.
If the data is not in a grid, you could extend the chip (as suggested by the commenter below), and the user is able to select the chip to change status:

From the Nielsen Norman group: Top 10 application mistakes
- Unlabeled icons:
It’s really rare for icons to stand on their own, with most users able to understand them immediately. Even icons that might seem universal (such as the hamburger menu) are not as familiar to users as most UX practitioners would expect.