In the West, the Vicksburg campaign, where Grant captured the last Confederate stronghold on the Mississippi, dividing the Confederacy into two parts, and enabling him to rescue the besieged Army of the Cumberland at Chattanooga. (This ended the war in the West).
In the East, Lee's spectacular success at Chancellorsville, followed by his historic defeat at Gettysburg, ending his hopes of invading Pennsylvania.
By the end of the year, Grant was on course to become General-in-Chief.