Xbox Game Pass
From Halopedia, the Halo wiki
Xbox Game Pass is a subscription-based service for Xbox One, PC (through the Microsoft Store), and the Xbox Series X that allows players to have access to most of Microsoft's 1st Party library and many Indie titles stemming from Microsoft's indie developer program. Game Pass for Xbox One was released on June 1, 2017 for $9.99/month USD.
During Xbox Games Showcase 2020, Microsoft announced that Project X-Cloud, Microsoft's new game streaming platform, would be included with Game Pass Ultimate at launch at no extra cost.
Xbox Game Pass includes the following Halo titles: