There are a lot of answers to this question. I doubt if I can answer all of them, but I'll try.
World War I was largely a technological war, employing aircraft and tanks for the first time in a major conflict. It was the first war in which submarines played a major role. Prior to the war, railroads in some of the countries were arranged to provide rapid movement of troops and supplies once there was a military mobilization. It was the first war in which radio (wireless telegraphy) played a significant part.
While it did not introduce machineguns, World War I saw them used on a greater scale than any previous conflict, largely rendering horse cavalry obsolete. World War I was the high point of the dreadnaught-type battleship and largely introduced battle cruisers in a significant surface role. The Battle of Jutland was the second full-scale fleet action since Trafalgar and there have been none since. The naval engagements of World War II ware larger in scale but involved greatly differing technologies.
After World War I the maps of Europe were redrawn. The German empire was broken up and the Austria-Hungarian empire ceased to exist. The Ottoman Turkish empire also was broken up. Austria, Poland, Hungary, Czechoslovakia, Yugoslavia and several other states emerged as independent countries.
Following World War I, the Russian empire had collapsed, replaced by the Union of Soviet Socialist Republics. The United States, the USSR and Japan emerged on the world stage as major players, although the transition would largely take more than two decades.
Warfare today has progressed in many ways following the innovations in World War I. Tank warfare and aerial warfare have evolved as technologies advanced. The battleship is now obsolete. Modern warfare also faces the changes brought on by the atomic age. Chemical warfare, used on a large scale in World War I, has been used on a smaller scale since, but is not now considered a practical weapon.
I would say modern warfare differs greatly from World War I, but retains many of the same principles. Weapons have changed and new technologies have come into play--space applications, missile technology, radar, and greatly improved aviation capabilities. Also, the computer has changed the dimension of war
World War I was an inevitable conflict, with roots going back well into the 19th Century. Some of the issues in World War I remained unresolved and World War II was in many ways an extension of World War II. Many of the conflicts since World War II--Korea and Vietnam, notably--were themselves extensions of World War II.
Hope this answer helps.