Let's start with Apple. This article from Tech Crunch goes into a lot of detail about the various accessibility advances coming up in Apple's various operating systems to be updated this fall: Apple’s global accessibility head on the company’s new features for iOS 13 and macOS Catalina.
Voice control is the first big advance discussed at the keynote. It purports to allow seamless movements between navigating, using apps and creating and sending content. The video shown at the keynote makes it all look quite usable.
And to learn more about other existing accessibility features in Apple software and devices, check out this article from iMore: Apple: Accessibility is a Human Right.
This CNET video from YouTube gives a good summary of Google's recent announcements at its annual I/O conference. The first part covers mostly accessibility features including text to speech using a phone's camera, AI assisted voice control, live captioning, etc.
Of course one of the downsides to Apple's offerings is that they're limited to Apple devices: iPhones, iPads, Macs, etc. As these devices tend to be more expensive, that can limit their reach. Google makes apps available on multiple platforms and the Android operating system runs on a wide variety of devices ranging from very cheap to high end. The problem is that Android Q may never run on most of the devices currently on the market. And, for now, some of the features are limited to Google's own Pixel devices.
Another major player in the accessibility arena is Microsoft. They produce apps like Seeing AI which is available for iOS (not yet for Android) and allows a user to point the device's camera at text and have it read aloud. It also attempts to identify objects in photos. When I tested it, it identified a red flower and my dog with a toy in his mouth as a brown dog with a frisbee - close enough. But when I asked it to identify a mountain range, it could only identify the clouds. It seems to default to grey a lot with colors and wanted to make my dog green. It was spot on with currency and identifying products by their barcode.
There's an entire section on the Microsoft website devoted to Accessibility In addition, they have a YouTube channel devoted to Accessibility Training called MSFTEnable which includes a number of training videos exploring how to use many of their accessibility features.