The following from Dane Ortlund, Crossway's Senior Vice President of Bible Publishing, is perhaps the best description of the Gospel Transformation Bible:
If other study Bibles perform the function of a lecture, the Gospel Transformation Bible is a sermon—not a “Do better!” sermon but rather a sermon that helps believers see how Christ is the point of the whole Bible, passage by passage. No other study Bible is intended to give believers a grace “lens” for reading the entire Bible. So while the notes of the Gospel Transformation Bible do a specific thing—highlight God’s redemptive purposes unfolding through history—the notes are not for a certain niche but for everyone, because everyone is a sinner in need of grace. In essence, our hope is for the Gospel Transformation Bible to help people unlearn the various wrong ways of reading the Bible that burden and deaden. We want to help people see the life-giving nature of the Word of God as a word of grace.