Short answers, pulled from the story.
Over three million Soviet soldiers were captured by the end of 1941, and two-thirds of them died from starvation, exposure, and disease by early 1942. At least 1.3 million Soviet prisoners had been deported to Germany or its annexed territories by the end of the war, with 400,000 not surviving.
Adolf Hitler rejected an offer from the Soviets to abide by the Hague provisions several weeks after the war started on the 22nd of June 1941. On the 30th of March 1941, Hitler stated privately that they must distance themselves from soldierly comradeship and ordered a war of extermination.
Two-thirds of over three million captured Soviet soldiers died from starvation, exposure, and disease by early 1942, representing one of the highest sustained death rates for any mass atrocity in history. Conditions were worse than civilian forced laborers or prisoners from other countries, with some camps having death tolls comparable to Nazi concentration camps.
An estimated 1.4 million Soviet prisoners served as auxiliaries to the German military or SS, making up 10 percent of German forces occupying France by D-Day in mid-1944. In 1943, there were 53 battalions raised from prisoners including fourteen in the Turkestan Legion and nine in the Armenian Legion.
Former prisoners did not receive reparations until 2015 when the German government paid a symbolic amount of 2,500 euros to the few thousand still alive. Families of defectors were sometimes arrested under an August 1941 classified order that declared surrendering commanders and political officers deserters to be summarily executed.