Research shows that since GDPR introduction overall, third-party cookies on news sites is down 22%.
Other figures are also interesting, and it's worth a read of the research from Reuters Institute, on the Oxford University web site.

It's interesting, the report suggests, that some news organisations are responding to GDPR either by obtaining consent for third-party tracking or by curbing the use of outside cookies in general.

The research covered Finland, France, Germany, Italy, Poland, Spain, and the UK from April to July, 2018, with the UK showing the greatest drop and Poland showing an increase.

Changes in Third-Party Content on European News Websites after GDPR (PDF) [reutersinstitute.politics.ox.ac.uk...]