Phase II Study of Second- Line Pembrolizumab Plus GVD for Relapsed or Refractory Hodgkin Lymphoma

Age 10-17: 2mg/kg (cap at 200mg), Age ≥ 18: 200 mg (flat) ,Day 1 of each 3 week cycle IV infusion 2-4 cycles (pre-ASCT)

1000mg/m\^2 Days 1 and 8 of each 3 week cycle IV infusion 2-4 cycles

20mg/m\^2 Days 1 and 8 of each 3 week cycle IV infusion 2-4 cycles

15mg/m\^2 Days 1 and 8 of each 3 week cycle IV infusion 2-4 cycles

Stem cell mobilization and collection will be performed as per standard MSKCC guidelines after 2-4 cycles of pembrolizumab-GVD.