Unbiased news is literally impossible now that "alternative facts" are in the mainstream. Take climate change for example:
Party A: "As greenhouse gasses increase, so too does the temperature according to historical measurements. We should do something about this."
Party B: "There is no way to measure the global temperature, and anyone claiming to have done so is working for Party A. We shouldn't address this at all."
Whether or not you as a journalist, were to include a factoid about it being the hottest summer on record, you're now doing biased reporting. Sure, if you include the fact you're siding with Party A and saying the fact is wrong is siding with Party B. However, not talking about it all is still siding with Party B, since that's their end goal. Factually accurate, inaccurate, and ambiguous are therefore all a form of bias.
The trick it to be biased towards truth and humility. If they choose which party to align with based on considerations other than considering which party believes what that would be an excellent start.
For example, in this case a publication could run an article saying that the hottest summer on record just happened, and present cases on how big a problem it is and how much in the way of resources should be dedicated to solving it - including the case for the whole thing being a non-issue. That'd be pretty good journalism. They'd probably manage to upset both parties or make both of them happy if they did that IMO.
Neither of those are factually accurate statements; they pair a claim to fact in the first half with a policy proposal in the second half. "We should/should not do something about this" is not a statement of fact, it's a value proposition. So if a media outlet is consistently pushing the same value proposition (namely, that we should expend considerable effort to counteract climate change), then it's biased, regardless of the factual accuracy of what they report.
Party A: "As greenhouse gasses increase, so too does the temperature according to historical measurements. We should do something about this."
Party B: "There is no way to measure the global temperature, and anyone claiming to have done so is working for Party A. We shouldn't address this at all."
Whether or not you as a journalist, were to include a factoid about it being the hottest summer on record, you're now doing biased reporting. Sure, if you include the fact you're siding with Party A and saying the fact is wrong is siding with Party B. However, not talking about it all is still siding with Party B, since that's their end goal. Factually accurate, inaccurate, and ambiguous are therefore all a form of bias.