Generally speaking, a gospel is good news that solves the problems of humanity. There are many gospels. Philosophers, religious leaders, and politicians all offer various gospels. The American Dream is a kind of gospel. But Paul declared that he was “set apart for the gospel of God.” In which gospel have you placed your hope?
Romans 1:1 Paul, a servant of Christ Jesus, called to be an apostle, set apart for the gospel of God. (ESV)