This is a type of Leaf-footed Bug, a group of true bugs named for their leafy flares on their hind legs. The markings on this one resemble a Western Conifer Seed Bug, which is known to routinely occur in MD despite originally being native in the western U.S. Adults are known to wander indoors for shelter since they overwinter.

Unlike the similar-looking assassin bugs, this one is not considered beneficial per se in that it's not a predator or pollinator, but neither is it considered to be a serious pest. You can release any you find in the house back outside, but you don't need to worry about those still outdoors. Sealing any gaps and cracks in exterior walls can help prevent more from finding their way in. Door weather-stripping, if worn-down in places, can be one easy way that they wander indoors.

Miri