From the teaser it seems one of the underlying themes in season 5 will be Freedom.. Freedom on Mars.
For All Mankind is exploring the idea of never ending space race if Soviets would have beaten US in the race for the Moon and the intention of the show is each season to jump about a decade further into the increasingly diverging reality of the show: in season 1, depicting alternate 1969 to 1974, both Soviets and US start building their separate bases near the lunar South pole; in season 2 (1983) both bases have been expanded and the superpowers compete for resources on the Lunar surface; in season 3 (1992 to 1995), Soviets and US are joined by a private company Helios and North Korea for a four way race to be first on Mars; in season 4 (2003) there is a sprawling international human base on Mars and an unexpected side enters the race to get hold on a large, lithium-rich asteroid for mining. Season 5 will start airing on March 27 on Apple TV
Here you can watch the teaser and see the accompanying photos:
Happy Valley Base has been expanded a lot since season 4:
Alex Poletov (Ed's grandson) rides a motorcycle near the Happy Valley Base:
Free Mars graffiti are all over the Happy Valley Base:

























