He is throwing his hat into the ring to replace City Councilmember Rosie Mendez, who is at her term limit.
The Observer has the story:
As a Republican, McMillan will face a steep uphill fight in the deep-blue district, which covers his home neighborhood of the East Village and the Lower East Side. Three Democrats are currently seeking the seat: Carlina Rivera, a local district leader and Mendez’s legislative director; community center director Jasmin Sanchez and attorney Mary Silver.
Here's a video interview with McMillan from yesterday...