By day, Robert Lis is a litigation and M&A partner at Greenberg Traurig in Warsaw. By night, he is host to five Ukrainian refugees who are living with him in his apartment.

Lis’s home is “not a big place—maybe the size of an American living room,” according to Richard Rosenbaum, executive chairman of Greenberg Traurig, which has 200 people, including 100 lawyers, in Warsaw.