What is the relationship between Crimea and Ukraine?

Crimea was incorporated into Russian territory from 1783, when yekaterina was the czar. After the October Revolution and the founding of the Soviet Union, it still belonged to the Russian Federation. At that time, Ukraine was also a member of the Soviet Union. Until 1954, Khrushchev somehow lost his mind. It is said to be to "celebrate the 300th anniversary of the alliance between Ukraine and Russia". Give Crimea to the Ukrainian people as a gift from the Russian people. This was originally the division of the Soviet Union's own domestic administrative regions. Of course, everyone has no opinion. Just like in 1950s, the State Council decided to assign several counties in Jiangsu Province, such as Songjiang and Chongming, to Shanghai. Who cares? The problem lies in the disintegration of the Soviet Union. In this way, Crimea, which is dominated by Russian-speaking Russians, is unwilling to be controlled by Ukraine. And hope to be independent or return to Russia. Therefore, everyone knows that the Crimean referendum will leave Ukraine and will undoubtedly pass. This is the root of the current Crimean issue.