Apologize for what?!
For asserting executive privilege, like Presidents have done for decades? Trump was defending Presidential authority granted by the Constitution from House Dems' usurpation attempts.
For asking Ukraine to investigate corruption that might have implicated Hunter and/or Joe Biden? The corruption was real, and being a Presidential candidate does not immunize Joe Biden from an investigation involving real corruption. Especially when Joe boasted on video of arm-twisting Ukraine to fire the prosecutor who was investigating that corruption. Trump was doing his job, properly!
No apology is warranted.