Well in very simplified terms the concordat of worms established the independence of the church from the states it operated within. Throughout the Middle ages there was a huge conflict between the holy roman princes, them being the rulers of their inherited lands, and the church. The princes wanted to appoint relatives and people that were willing to pay large sums for the offices of the church.

The church created huge amounts of wealth through the land they owned, taxes (tithes), and gifts they received, so the princes wanted in on that. Also it's very handy to have great spiritual control over the souls of your subjects.

The pope didn't like it a bit and had no intention of sharing his powers, and basically he won in the struggle against the princes.

Much later the reformation was basically a continuation of that struggle, even though Luther based his critique on theological grounds, the princes had more worldly things in mind and saw a chance to gain more power at home by being against the papacy, or supporting it to snatch a neighbours territory on the grounds of him being a heretic.

In a way a lot of European history up until the age of enlightenment evolved around the struggle between church and state, and who has the right to do what.