According to the Chicago Sun-Times, the Cubs have purchased the McDonald's that is located across the street from Wrigley Field's main entrance on the northwest corner of Clark & Addison in Chicago:
A limited liability corporation owned by the Ricketts family, owners of the Cubs, has acquired a parcel of land across from Wrigley Field for future development of a "mixed use entertainment" project — in addition to the long-stalled triangle building.
Cubs spokesman Julian Green said the land at 3260 N. Clark — acquired by Ricketts-owned North Clark LLC — is now occupied by a McDonald’s, which would remain open for the foreseeable future.
Green wouldn’t discuss specific plans for the property or how much it cost.
The article goes on to say that plans for the triangle building could be altered from the original, which had a seven-story building with a parking garage, to include less parking and more open space, including the possibility of an ice rink in the winter and concert stage in the summer. The drawing at the top of this post shows one of the proposals for a "Cubs Alley" that would be in between the triangle building and Wrigley Field.
Possible uses for the property that the Cubs are buying would be another building which might include more office space or player workout facilities. Those were supposed to be in the triangle building but with its downsizing, might not all fit in there. What a "mixed-use entertainment project" might be is unknown, although that could just be technical wording that would allow the Cubs to do whatever they need to with the property.
According to Crain's Chicago Business, the purchase price of the lot (which includes the McDonald's and its adjacent parking lot) was $20 million.