From Muppet Wiki

10 Sesame Street is a building on Sesame Street. A brick two-story building that adjoins the Subway Station, the location was one of the "around the corner" locations that debuted on Sesame Street in Season 25.

The bottom floor of the building is leased to the Finders Keepers shop. The second floor is allocated as office space, although the only business shown is Celina's Dance Studio, in #213. The building, and its tenants, have not been seen on Sesame Street since the expanded street sets were dropped following Season 29.