Although Apple offers Radeon graphics cards in its Macs, the company has yet to use AMD's processors. However, multiple lines of code reported by hardware leaker @_rogame as being from the latest macOS Catalina 10.15.4 operating system (OS) beta suggest that Apple might shift over to AMD chips in the future.
There's no evidence that Apple will completely ditch Intel for AMD. However, if the lines of code are real, the inclusion of AMD processors in Apple's OS implies that the U.S. tech giant is open to the possibility of offering its products with AMD processors. It's also possible that Apple is already testing AMD's offerings at this moment.
The code inside macOS Catalina 10.15.4 beta references several AMD APU codenames, including Raven, Picasso and Renoir. There is even mention of Van Gogh, the rumored codename for AMD's upcoming APU.
AMD recently announced the Ryzen 4000-series Renoir APUs based on the Zen 2 microarchitecture and built on the TSMC 7nm FinFET manufacturing process. The Renoir lineup spans from four up to eight cores, so there is some diversity to appeal to Apple.
Other bits of code refer to a plethora of unreleased AMD Navi silicon, including Navi 12, Navi 21, Navi 22 and Navi 23, that also previously appeared in a Linux driver. The latter three are rumored to feature the new RDNA 2.0 architecture and TSMC's enhanced 7nm+ node. It's not hard to imagine Apple jumping on the Navi bandwagon, considering AMD Polaris and Vega-powered graphics cards are commonly found inside Apple products.
Apple's Worldwide Developers Conference (WWDC) starts on June 3. If the company is preparing any new products, it'll likely announce them there. We'll keep our eyes peeled to see if there are any AMD chips in them.