WNBA star Brittney Griner was sentenced to 9 years in prison in Russia. How likely is a prisoner swap?

In Moscow on Thursday, WNBA star Brittney Griner was sentenced to nine years in prison on drug charges. Griner was detained at the airport in Moscow in February, after security found vape cartridges with cannabis oil in her luggage. Last month, Griner pleaded guilty to possessing the drugs, but said she packed them by mistake.