TL;DR: a marketing person insisted that any review of this particular monitor be tested a specific way, presumably because it looked good with those particular tests, and asked to be able to see drafts of reviews before publishing, and mentioned compensation for same. When HWUB told them that wasn't going to happen, the response was "we're afraid a bad review will hurt sales of this monitor, and we're going to have to ask you not to publish our review if you won't do what we tell you."
Hardware Unboxed are the guys that briefly got blacklisted by nVIdia last year for not fluffing RTX.