There is no modern substitute for the gospel. Thus the gospel is simply the good news that the Lord Jesus Christ, the Son of God, has also become man, that He might die in atonement for the sins of man, and then, after His body was buried for three days, rise again from the grave, forever settling man's sin-debt before a holy God.
Men may talk about a “social gospel,” a “full gospel,” a “new gospel,” or some other gospel, but there is only one gospel, and that is the “everlasting gospel” (Revelation 14:6). No wonder Paul said:
"But though we, or an angel from heaven, preach any other gospel unto you than that which we have preached unto you, let him be accursed" (Galatians 1:9).
The gospel is still the good news, and there will never be another.