Ctrl, not Cmd, is Maya's main modifier on Mac. Unlike most Mac apps, Maya keeps the physical Ctrl key as its primary modifier for tool and viewport hotkeys. Cmd only doubles as an alternative for a handful of standard File and Edit menu commands (New, Open, Save, Save As, Exit, Undo, Redo, Cut, Copy, Paste).
Alt maps to Option. Anywhere Maya's reference lists Alt, press Option on a Mac keyboard.
Marking menus. Several letters (S, U, O, H) open a marking menu instead of a single action; which item fires depends on which mouse button you hold down while the key is pressed.
Exposé conflicts. F9-F12 can collide with macOS Mission Control/Exposé shortcuts. If that happens, remap either Maya's hotkeys or the system shortcuts in macOS System Settings.