Pte Henry Wallington and Pte Frank Mead, of the 23rd (County of London) Battalion, were identified using DNA samples from relatives. WW1 soldiers buried after 'emotional' DNA match
DNA identification is amazing, but obviously you need relatives' samples to compare. I went to a talk a few years ago by someone from the Dutch Army who IDs and buries WWII casualties that are still being discovered. He told us the story of the body of a man who had mistakenly been shot by the resistance, one of whose members had decided to disclose where the grave was after years of carrying the guilt. Unfortunately, there was no living relative to compare the DNA of the dead man against in order to get a confirmed ID. However, they discovered his brother had sent a letter to the Red Cross after the war in the hope they might know where his sibling was. They managed to get a DNA sample from the brother's saliva used to seal the letter and got a match that way.