This may not belong here in astronomy and my apologies if that's the case.
We find, and are able to travel to (in a reasonably short amount of time), a planet that is for all intents and purposes a second earth: it has close to the same atmosphere, gravitational force, a stable orbit, land and liquid water, preferable temperatures, vegetation and other life , etc...
From a 'War of the Worlds' approach to this, wouldn't it stand to reason that we still would not be able to land on the planet and exit our spacecraft without suits to protect us because of the fundamental aspect of our immune systems? That is, our bodies have adapted and continue to adapt to Earth's lifeforms but have absolutely no tolerance to another planet of almost identical properties and therefore would perish shortly after exposure, yes? So I wonder, does anyone know if there is a plan for the hypothetical scenario to gradually expose individuals to the new environment and if so, what is the plan? For example, we could try to collect at least some of the potentially hazardous bacteria and viruses for vaccination? (maybe, not sure how that works even on Earth)