Maidan
Here Lisa alludes to the coup d'état which took place in Ukraine in 2014. It is known under the names "revolution of dignity" and "Maidan".
In late November 2013, the then-president Viktor Yanukovich announced he will wait for six months before signing the association agreement between the EU and Ukraine. If Ukraine accepted this agreement, it would have to cut its ties with Russia which until 2022 was its most important economic partner.
This led to protests at the Maidan nezalezhnosti (Independence Square) in Kiev.
In February 2014 the protests turned violent. About 100 people were killed during the unrest, including by snipers.
Yanukovich resigned. All the post-Maidan regimes took a course on being Westernized (incl. the attempts to make Ukraine a member of the EU and NATO).
This led to protests in the Russia-leaning regions of East and South Ukraine. Soon after the Maidan the predominantly Russian Crimea joined the Russian Federation. In April 2014, the Donetsk and Lugansk People's Republics were formed.
The Ukrainian government started a so-called anti-terrorist operation (ATO) with the declared goal of bringing the two republic back into Ukraine. In June, the newly elected president Petro Poroshenko intensified the ATO.
Petro Poroshenko owned and managed several confectionery factories in Eastern Europe.
The (probably) best introduction to the history of the conflict in Ukraine in English language
UnCommon Core: The Causes and Consequences of the Ukraine Crisis, John Mearsheimer