Yes. Rocket League works cross-platform. To double-check the option is enabled, go to Main Menu > Options > Gameplay tab, and put a checkmark in front of Cross-Platform Play if it isn't there. This applies to grouping up with or against players on platforms other than yours. You can also, sync your progress and inventory cross-platform if you link separate accounts to the same Epic Games account. To do so, visit the game's Account Activate page.