The executive summary of several years of news on this issue is roughly as follows: Qualcomm owns a crap-ton of patents, which makes it difficult (and expensive) for anyone else to engineer an acceptable cellular modem that doesn't infringe upon those patents. Qualcomm knows that they have everyone else over a barrel, so they charge steep fees for their modems to all cell phone vendors.
In 2011, Intel bought another company which was developing their own modems to compete against Qualcomm, but Intel eventually gave up on this; thus, in 2019 Intel sold their entire cellular modem business to Apple. Apple has been attempting to continue that work, in order to get away from having to rely upon Qualcomm.
If Apple finally succeeds, Qualcomm will lose their strangle grip on the cellular modem industry, and everyone -- Apple customers and otherwise -- will likely benefit. (Except for Qualcomm, of course.)