Christ died for all, so that those who live should live no longer for themselves, but for Him who died for them and rose again. Now all things are of God, who has reconciled us to Himself through Jesus Christ, and has given us the ministry of reconciliation, Now then, we are ambassadors for Christ, as though God were pleading through us: we implore you on Christ’s behalf, be reconciled to God. For He made Him who knew no sin to be sin for us, so that we might become the righteousness of God in Him. 2 Corinthians 5, NKJV

So that is a subordinating conjunction that introduces a clause of purpose or result, often indicating an action taken with a specific goal in mind. This series explores the so that of the providence of God. See here.