Depictions of the later development of a victorious Confederacy vary considerably from each other – especially on two major, interrelated issues: an independent Confederacy's treatment of its Black population and its relations with the rump United States to its north.
In the 1900 Hallie Marshall: A True Daughter of the South by Frank Williams, the earliest known Civil War alternate history, the Confederacy won by mobilizing black slaves to its army, their participation turning the tide at Gettysburg. Thirty years later, the independent Confederacy is full of happy, well-treated Black slaves feeling perfectly content under the benevolent, paternalistic planters - comparing favorably with the rump US which is torn by a brutal class struggle, with nominally free factory workers protesting inhuman working conditions or starving in unemployment.
However, most other alternate histories assume that, even when succeeding in becoming independent with its "peculiar institution" intact, the Confederacy would have still eventually put an end to slavery.
In Gray Victory, set in the immediate aftermath of the war, the Confederacy is faced with both subversion by Northern Abolitionists and the increasing organization and assertiveness of Black Southerners themselves, and the story gives the clear impression that, no matter who wins, the end of slavery is inevitable.
In Bring the Jubilee Blacks, despite President Lee's grand gesture, remain disenfranchised into the 20th Century (as are the people of Latin America who were in this timeline annexed by the Confederacy and the Confederacy's immigrant population).
The same is true for Harry Turtledove's Southern Victory series – where it is President James Longstreet who frees the slaves from being property, as a prerequisite for retaining British and French support for the Confederacy in the Second Mexican War, but Confederate Blacks remain a very oppressed and discriminated underclass, denied basic civil rights and not even being allowed to have surnames. In later volumes of the series the Blacks burst out in a brutal armed revolt called the Red Rebellion during the Great War which are met with equal brutality from White authorities, who then make them the target of a terrible Holocaust-like genocide.
In Bring the Jubilee, the rump United States is completely broken down by its defeat, becoming an impoverished and backward country while the Confederacy goes on to annex everything to its south as far as Tierra del Fuego (barring the Republic of Haiti) and become a major world power.
In Grey Victory, Abolitionists seek to provoke the U.S. and the C.S. into a new war. In By Force of Arms, an attempt at reconciliation fails and after a few years they are at war again.
More optimistic results occur in The Guns of the South and several other works, where the two nations settle down into reasonable good neighborly relations within a few years of the war's end, and in some cases agree to reunite as one nation after 50 or 100 years of being apart.
By stark contrast, in Southern Victory they develop into hereditary enemies who go to war again every decade or two and who spend the rest of the time preparing for new war, becoming entangled in webs of worldwide military alliances.
In the 1914 of Southern Victory, U.S. and Confederacy are drawn into the worldwide war immediately following the Archduke's murder, and open an American front of trench warfare, every bit as terrible as the ones in Europe. Conversely, the 1914 of "A Hard Day for Mother" in Alternate Generals 1 by William R. Forstchen sees the amicable treaty of reconciliation and voluntary reunification between the two nations.
In If the South Had Won the Civil War by MacKinlay Kantor, reunification comes later: during the 20th Century the United States, Confederate States of America and Texas (which seceded from the C.S.) become economically integrated and in both World Wars, they all fight against Germany as close allies. Following World War II, U.S., C.S., and Texas all feel threatened by Soviet missile bases and armored brigades in Alaska (which was never purchased from Russia). Therefore, they announce a formal reunification in 1961, on the precise centennial of Fort Sumter. Conversely, a GURPS game setting book presents a 1993 in which the U.S. and C.S. still watch each other warily across an armed border that stretches to the Pacific.