I don't think so. See Subtractions.

What's New for the Tax Year (marylandtaxes.gov) 

It doesn't mention spouse.

I would say yes.
v. Up to $15,000 in income from an employee retirement system that is attributable to service as a public safety employee for a taxpayer who is age 55 or
older on the last day of the taxable year. To qualify, you
must be a retired correctional officer, law enforcement officer, or fire, rescue, or emergency services personnel of
the United States, Maryland, or a political subdivision of
Maryland. Only subtract income that you included on your
federal return as taxable income received as a pension, annuity or endowment from an “employee retirement system”
qualified under Section 401(a), 403 or 457(b) of the Internal
Revenue Code

I read that, too.

It says "you" and not spouse or surviving spouse

" To qualify, you must be a retired correctional officer, law enforcement officer, or fire, rescue, or emergency services personnel of the United States, Maryland, or a political subdivision of
Maryland."

I agree with Susan.

If you take a look at Md. Tax-General Code Ann. §10-209, which governs the new subtraction, there is no reference to the death of a taxpayer or the surviving spouse.  The only reference to the entitlement in relation to a spouse is in subsection (b) where the spouse is totally disabled:

https://advance.lexis.com/documentpage/?pdmfid=1000516&crid=0664959b-7208-4fd5-92d2-26103412cf66&nod...

In contrast, if you refer to §10-754, which is for the Senior tax credit that was added by the same House Bill 1468, there are clear references to surviving spouses in two subsections:

https://advance.lexis.com/documentpage/?pdmfid=1000516&crid=10ab04ba-b5c8-4dae-ad8e-86b1a07bf0b1&nod...

If there was an intention for a surviving spouse to benefit from the subtraction, there would have been no reason for §10-209 to not include such references.

 Thanks Jensen.

I didn't feel like taking the time to look up the code.

(Although that would have been a better use of my time than the military person selling a rental at a loss with depreciation recapture)