When comparing the iPhone 15 Pro Max and the iPhone 16 Pro Max in terms of Apple Intelligence and other key features, here are the main differences:

Display Size
iPhone 15 Pro Max: 6.7-inch Super Retina XDR display.
iPhone 16 Pro Max: 6.9-inch display, making it the largest iPhone ever made.

Camera System
iPhone 15 Pro Max: 48MP Main camera, 12MP Ultra Wide camera, and a 5x Telephoto lens only on the Pro Max model.
iPhone 16 Pro Max: 48MP Fusion camera, 48MP Ultra Wide camera, and a 5x Telephoto camera on both Pro models. The new camera system supports 4K120 fps video recording in Dolby Vision and includes a faster quad-pixel sensor.

Apple Intelligence
iPhone 15 Pro Max: While it will receive some Apple Intelligence features, it is not built around this concept like the iPhone 16 Pro Max.
iPhone 16 Pro Max: Specifically designed with Apple Intelligence in mind, offering features like changing the tone of messages, improved Siri, augmented searching through photos and videos, and new camera controls.

Capture Button
iPhone 15 Pro Max: Does not have a dedicated Capture button.
iPhone 16 Pro Max: Includes a new, fully capacitive Capture button located below the power button, which provides quick access to camera features and AI-driven insights.

Battery Life
iPhone 15 Pro Max: Smaller battery compared to the iPhone 16 Pro Max.
iPhone 16 Pro Max: Features a larger 4,676mAh battery, expected to deliver better battery endurance.

Processor
iPhone 15 Pro Max: Powered by the A17 Pro chip.
iPhone 16 Pro Max: Powered by the more advanced A18 Pro chip, which is faster and more efficient.

Additional Features
iPhone 16 Pro Max: Offers studio-quality mics for better audio recording, including spatial audio and pro audio recording settings.
In summary, the iPhone 16 Pro Max offers significant upgrades in display size, camera capabilities, processing power, and battery life, along with new features like the Capture button and enhanced Apple Intelligence integration.