Testing the Addition of Tazemetostat to the Immunotherapy Drug, Pembrolizumab (MK-3475), in Advanced Urothelial Carcinoma

University of Pittsburgh Cancer Institute (UPCI), Pittsburgh

University of Kentucky/Markey Cancer Center, Lexington

Mayo Clinic in Rochester, Rochester

Northwestern University, Chicago

University of Kansas Cancer Center - Lee's Summit, Lee's Summit

University Health Truman Medical Center, Kansas City

University of Kansas Cancer Center at North Kansas City Hospital, North Kansas City

University of Kansas Cancer Center - North, Kansas City

Lawrence Memorial Hospital, Lawrence

The University of Kansas Cancer Center - Olathe, Olathe

University of Kansas Clinical Research Center, Fairway

University of Kansas Hospital-Westwood Cancer Center, Westwood

University of Kansas Cancer Center-Overland Park, Overland Park

University of Kansas Health System Saint Francis Campus, Topeka

Mercy Hospital Pittsburg, Pittsburg

Salina Regional Health Center, Salina

HaysMed, Hays

Mayo Clinic Hospital in Arizona, Phoenix

Mayo Clinic in Arizona, Scottsdale

Smilow Cancer Hospital-Derby Care Center, Derby

Smilow Cancer Hospital Care Center-Fairfield, Fairfield

Smilow Cancer Hospital Care Center - Guilford, Guilford

Smilow Cancer Hospital Care Center at Saint Francis, Hartford

Smilow Cancer Center/Yale-New Haven Hospital, New Haven

Yale University, New Haven

Yale-New Haven Hospital North Haven Medical Center, North Haven

Smilow Cancer Hospital-Orange Care Center, Orange

Smilow Cancer Hospital-Torrington Care Center, Torrington

Smilow Cancer Hospital Care Center-Trumbull, Trumbull

Smilow Cancer Hospital-Waterbury Care Center, Waterbury

Smilow Cancer Hospital Care Center - Waterford, Waterford

Mayo Clinic in Florida, Jacksonville

Dartmouth Hitchcock Medical Center/Dartmouth Cancer Center, Lebanon

University Health Network-Princess Margaret Hospital, Toronto