People nowadays commit fraud in ways that we wouldn't have thought possible many years ago.
この場合、次のような言い方ができます。
ーPeople nowadays commit fraud in ways that we wouldn't have thought possible many years ago.
「近頃、昔では考えられなかった方法で不正を行うようになった」
to commit fraud で「不正を行う」
in ways that we wouldn't have thought possible で「可能だとは思わなかった方法で」
ーPeople have learned to commit fraud in ways that you couldn't have imagined a long time ago.
「昔は考えもつかなかった方法で不正を行うようになった」
in ways that you couldn't have imagined で「考えもしなかった方法で」
ご参考まで!