The first episode of 'Halo' is free to watch on YouTube for one week

engadget.com:

You don't have to start a Paramount+ trial just to figure out whether or not the Halo TV series is worth your time. The streaming service has made the first episode of the game-inspired show free to watch on YouTube for a week starting March 31st (sorry!). The freebie is only viewable in the US, but it's worth a look if you want to see Hollywood's take on Master Chief and the Covenant.

There's no mystery behind the strategy. Paramount+ is clearly hoping to build Halo's viewer base (and thus the subscriber base) as quickly as possible, and a free sample might help when trailers aren't enough. The provider has used this approach before with releases like Star Trek: Picard.

It might also be a question of seizing on early success. Paramount+ was confident enough in Halo to renew it before the premiere, and that support was apparently well-founded. Deadline reported that the series broke the service's one-day premiere viewership record, ousting the Yellowstone prequel 1883. While Paramount+ is still small compared to heavyweights like Amazon and Netflix, sustained interest in Halo could help the streamer grow and reduce its dependence on Star Trek.