The heading speaks of this as the prayer of Moses. 
Moses is mentioned 8 times in the Psalms and 7 of those 8 are in Psalms 90-106. 

Psalm 90 stresses 
The Eternity of God- 90:1-2, 4
The Sovereignty of God- 90:3, 5 God holds man's life in His hand
The Wrath of God against sin- 90:7, 9, 11. God is also a God of lovingkindness- 90:14

This Psalm stresses the brevity of man's life- 90:3, 5-6, 10, 12
It stresses that man is frail, weak, and dependent upon God

The link between sin and death is shown in the earliest chapters of the Bible- Gen. 2:17; 3:19.
Romans 5:12-21 and Romans 7:7-25 continually use the words sin and death. But Jesus' death for our sins and His resurrection have made it possible for us to be forgiven and to have eternal life- Romans 5:21; 6:23; 7:25.