What advice do you have for a CIO coming into an organization where the CFO historically has viewed IT primarily as a cost center and is demonstrating more resistance to change that you anticipated during the interview process?

Run the IT as a business.

Stop trying to justify the investments to CFO or CEO, you will continue to suffer and it wouldn't work.

You need to find a way to allocate the cost of IT to business units, not only business applications but also the hidden infrastructure and cybersecurity components (This requires an effort to collect the inventory of all IT assets, and allocate the cost of each component and tool to business applications and business users, this will show the actual running cost of each system).

Business units have to assume ownerships on their IT expenses, and held accountable for the investments the organization makes in technology, they need to defend the investments they want to make, so it is their problem not yours.

Typically, investments and expenses related to regulatory mandates face much less resistance than those for business, and business applications even face much less resistance than infrastructure, data, and cybersecurity.

Relationship with the CFO should be managed as partnership in rationalizing the investments.  

You have exactly three options.

1) Convince the CFO that IT is a strategic imperative and revenue producer rather than a cost center.  Completely change their thinking.   This is the best and most difficult option.  The CFOs that fail to realize this are either in an unimpacted industry (will there be any?) or are setting themselves and the company up for a serious competitive disadvantage.

2) Find a new job immediately if there is no possibility of fixing the situation.

3) Sell the CEO and BoD on the strategic value and have them impose the 'right thing' even if the CFO pushes back.  This is undesirable for a lot of reasons but at the end of the day, the CEO sets strategy and the CFO supports execution of that strategy.  

If both the CEO and CFO fail to appreciate the significance of AI and IT, I'd run for the hills.  It won't end well.

Is the CFO not sold on the value of IT or doesn't understand the potential of IT or is it due to some bad experiences/advice in the past with IT investments?