AHSCT indicates autologous hematopoietic stem cell transplant; CMR, complete metabolic response; CR, complete response; ICE, ifosfamide, carboplatin, and etoposide; PD, progressive disease; PEM, pembrolizumab; PET2, 18F-fluorodeoxyglucose–positron emission tomography with computed tomography assessment after 2 cycles of combined PEM and ICE chemotherapy and 1 cycle of PEM monotherapy; PR, partial response; and TLI, total lymphoid irradiation.