A Study of Pembrolizumab (MK-3475) in Relapsed or Refractory Classical Hodgkin's Lymphoma (rrcHL) or Relapsed or Refractory Primary Mediastinal Large B-cell Lymphoma (rrPMBCL) (MK-3475-B68)

Wits Clinical Research ( Site 0904), Johannesburg

Groote Schuur Hospital ( Site 0906), Cape Town

Centre Hospitalier Universitaire Dijon Bourgogne - Hôpital François Mitterrand ( Site 0401), Dijon

Anne Arundel Medical Center-Anne Arundel Oncology and Hematology ( Site 0125), Annapolis

Fondazione IRCCS Policlinico San Matteo ( Site 0509), Pavia

Ege University Medicine of Faculty ( Site 1105), Bornova

CNPE Regional Center of Oncology ( Site 1305), Kharkiv

Tulane Medical Center ( Site 0110), New Orleans

Istituto Nazionale Tumori IRCCS Fondazione Pascale ( Site 0503), Napoli

Az. Osp. Ospedali Riuniti VILLA SOFIA-CERVELLO-EMATOLOGIA I ( Site 0507), Palermo

Lundquist Institute for Biomedical Innovation at Harbor-UCLA-Hematology and Medical Oncology ( Site, Torrance

Gustave Roussy ( Site 0402), Villejuif

The National Medico-Surgical Center N.I. Pirogov ( Site 0801), Moscow

Moscow City Clinical Hospital S.P. Botkin ( Site 0803), Moscow

Almazov National Medical Research Centre ( Site 0807), Saint Petersburg

Hospital Erasto Gaertner ( Site 1703), Curitiba

Fundação Pio XII - Hospital de Câncer de Barretos ( Site 1701), Barretos

Cross Cancer Institute ( Site 0207), Edmonton

Fakultni nemocnice Brno Bohunice-Interni hematologicka a onkologicka klinika ( Site 0302), Brno

Fakultni nemocnice Kralovske Vinohrady-Interni hematologicka klinika ( Site 0303), Prague

Fakultni nemocnice Hradec Kralove-IV. interni hematologicka klinika ( Site 0304), Hradec Králové

Szpital Kliniczny im. Przemienienia Panskiego Uniwersytetu M-Oddzial Hematologii i Transplantacji S, Poznan

Pratia MCM Krakow ( Site 0064), Krakow

Uniwersyteckie Centrum Kliniczne-Klinika Hematologii i Transplantologii ( Site 0063), Gdansk

Netcare Pretoria East Hospital-Albert Alberts Stem Cell Transplant Centre ( Site 0902), Centurion

Ankara University Department of Hematology, Clinical Research Unit ( Site 1101), Ankara

National Cancer Institute ( Site 1303), Kyiv