Ukraine remains in the CIS
Despite the declarations, Kyiv never applied to leave the Commonwealth of Independent States.
Chairman of the CIS Executive Committee Sergei Lebedev spoke about this in an interview with Izvestia.

“Ukraine legally remains part of the Commonwealth of Independent States. We even maintain offices in the CIS executive committee assigned to Ukrainian representatives. And although de facto Ukraine, unfortunately, has curtailed its participation, we are especially concerned by the fact that it is refusing to participate in some treaties and agreements that it previously signed. This is not in the interests of the citizens of Ukraine, not in the interests of other CIS states,” Lebedev said.
He also said that the CIS was closely monitoring the progress of the elections in Ukraine and was carefully studying what the newly elected President Vladimir Zelensky was saying now.
“I sent him congratulations on his election and expressed hope that Ukraine will return to constructive and mutually beneficial cooperation within the CIS. I am sure that life itself will tell Ukraine the right decision. And it lies in the fact that you need to be friends with your neighbors and build constructive relationships. We really hope so,” said the chairman of the CIS executive committee.
Earlier, as PolitNavigator reported, Ukrainian President Petro Poroshenko instructed the government to begin Ukraine's withdrawal from the CIS.