The captured members of the German 6th Army were by in large sent to Siberia, or at least to the east of the country to get them as far from the battle lines as possible. They were basically used for forced labor, suffered from ill clothing and malnutrition and general poor treatment. Out of the roughly 100K+ prisoners of the 6th, only @6,000 survived the war to be repatriated, some were not released until the early 1950s.

(Christina Morina, Legacies of Stalingrad: Remembering the Eastern Front in Germany since 1945)