Commonwealth of Independent States

The Commonwealth of Independent States (CIS) was formed in 1991 following the dissolution of the Soviet Union.  It's not the successor to the Soviet Union but it kind of is even though it's not. 

Today the CIS consists of Armenia, Azerbaijan, Belarus, Kazakhstan, Kyrgyzstan, Moldova, Russia, Tajikistan, and Uzbekistan.  In 2005, Turkmenistan became an observer member.  In 2008, Afghanistan and Mongolia became observer members.

Georgia withdrew its membership in 2008 following the five-day war when Russia invaded and took control of South Ossetia.

Ukraine withdrew in 2018 following the Russian annexation of Crimea in 2014 and Russian support of two separatist regions in Eastern Ukraine.

The three Baltic states, Estonia, Latvia, and Lithuania, chose not to participate because they viewed their being in the Soviet Union was an illegal occupation.

Headquarters for the CIS are in Minsk, Belarus.

The goal of the CIS is to coordinate policies regarding its members' economies, foreign relations, defence, immigration policies, environmental protection, and law enforcement.

The CIS spawned three organisations.  

The Collective Security Treaty Organization is a military alliance.  Kind of like the new Warsaw Pact but made up of former Soviet republics.  

The Eurasian Economic Union is basically the Eurasian version of the EU but only consisting of Armenia, Belarus, Kazakhstan, Kyrgyzstan, and Russia.

The Union State is the union of Belarus and Russia with the goal of common government, flag, currency, etc.

Following the breakup of the USSR, athletes competed at the 1992 Winter and Summer Olympics in team events as part of the CIS "Unified Team".  Athletes competed under the Olympic flag.  Since 1992, athletes no longer compete as a unified team and compete for their home countries.