She continued, “Thank you to my dad, grandfather, and my uncles who served proudly. Thank you to all of the heroes who sacrificed everything on #September11 to protect others and defend our liberty. We owe you everything.”
Since Maria has so many family connections to the military, her dog tags might be in connection to any of the family members she mentioned in her caption.
Source: https://www.distractify.com/p/why-does-maria-bartiromo-wear-dog-tags