1. This article is making contentions about Trump's phone call that are not supported by the transcript.
This is what Trump actually said:
As you can see, Trump didn't ask for any investigation into the Biden family. He asked Zelenskiy to provide whatever help he might have to our AG. And, Trump didn't ask Zelenskiy to investigate Burisma at all so there was no pressure from Trump regarding any such investigation.
2. The time frame of Hunter Biden's involvement with Burisma is irrelevant to any concern Trump had, since Trump's concern was with the actions of Hunter's father. Trump said nothing to Zelenskiy about investigating Burisma...or Hunter, for that matter. Any action Ukraine takes concerning Burisma...whether it involves before, during or after Hunter worked for them...is entirely the decision of Ukraine.
Also of note, Zelenskiy expressed to Trump that he is very concerned about corruption in his country and that he will do whatever he can to address that issue and he also asked Trump's help in his efforts.
3. One more point: In regard to any US investigation into possible criminal action by VP Biden, it doesn't matter if Hunter was involved with Burisma during the timeframe that Burisma was being investigated or not. What matters is that Hunter was involved with that company when Biden applied his billion dollar pressure.
So...don't get too excited about the news in this article. Besides the factually incorrect information it contains, the point the article makes is irrelevant.