In fact there is a fundamental difference between the mediation of the Lord Jesus Christ and the intercessions of the saints
The mediation of the Lord Jesus Christ is an atonement, which means that He mediates for the forgiveness of our sins, being the Atoner who paid our debts on our behalf. His mediation means that He says to the Father: "Do not count their transgressions because I have carried their iniquity" (Is.53:6). Thus He stands as a Mediator between God and men; or rather, He is the only Mediator between God and men; He fulfilled God’s Divine Justice and granted people the forgiveness of sins, by dying for them.