There's an entire branch of medical science that involves going to strange places (including places like subway door handles, not just wilderness), taking samples of microscopic life, and testing them for classification and potential for pharmaceutical value.
About 90% of all observed microorganisms are poorly understood because no one has figured out how to grow them in culture.
(I read this recently, probably on Wikipedia, but I don't have a proper citation.)
There are about 1.2 million species formally described, of an estimated 8.7 million species total. Bacteria and some other microorganisms are excluded from those counts because their mutability makes them resistant to formal classification.
https://www.bbc.com/news/science-environment-14616161
When I took my "classification of plants and animals" class, no one knew Archaea existed, and people argued about whether to place single cell life in a third kingdom, without really considering that eukaryotes and prokaryotes were more significantly different from each other than plants and animals.
Recent scientific news reported a life form that was believed to be able to substitute arsenic for phosphorus in its nucleic acids. That turned out to be wrong, but it illustrates the possibility of alternate chemistries of life. Some cultivars of sunflowers can, however, concentrate two percent or more of arsenic in their tissues, which makes them really toxic to lots of things, but useful for cleaning up arsenic pollution.
Scientists built a microorganism in culture that used two additional nucleic acid bases (besides the normal adenine, thymine, guanine, cytosine, and RNA-only uracil), and got it to reproduce reliably. That's more space for alternative chemistry of life.
Earth life always uses L amino acids, D sugars, and right-twisting nucleic acids. One or more could be reversed to make an alternative chemistry of life, or life forms that use both. One might find a world with more than one set of incompatible life. Imagine Earth life that could get carbohydrates from D-D life, but couldn't digest the D amino acids and had to eat something else for usable protein. Or imagine a world where Ancients had tinkered with Terran life to created an invert-Terran partial ecosystem that no one had bothered to study because the largest life forms in the invert ecosystem that survived are colenterates.
Star Trek and Traveller canon both include silicon life.
There are 11000 worlds in the Imperium, and 327 in Trojan Reach. There's no shortage of stuff for a xenobiologist to do.
But what can a xenobiologist do as an adventurer? I think the biological niche sample collector offers plenty of fun.
"No, this world's atmosphere is rated 'insidious'. We're not even going to land there."
"But no one has ever sampled the life in the Cadmium Hot Springs area. And I spent a fortune on special environment suits guaranteed to four standard hours in a hot chlorinated atmosphere. I braved laser fire in that shabby Ablat suit to bring back that wounded Glorious Empire trooper alive so you guys could interrogate him, and then you spaced him without even trying to sell him for ransom. Give me a couple of hours on the surface."
"Captain, Doctor Science has a point. And I think we have space enough in the hold for decontamination."
