If we introduce any disease or deadly effect to a large group of living things, will such a group be able to develop a resistance?
I don't think this answer answers the post given the discussion and new edits. I will leave it here nevertheless just in case I still misunderstand the OP's question.




  [..] introducing cancer or radiation [..]


A cancer is not a transmissible disease (except very few cancer last the facial tumor in Tasmianian devils). A radiation is not even a pathology, it is a physical phenomenon which include light. Did you rather mean something like a virulent flu for example?


  If we introduce any disease or deadly effect to a large group of living things, will such a group be able to develop a resistance?


The population may or may not survive. It depends upon many parameters such as how virulent is the parasite, how large is the population, whether individuals in the population have already encountered the parasite before, whether there is already genetic variants resistant in the population or whether de novo mutations will be needed, etc... There is no way to answer to this question in the general sense.

Note by the way, that an individual may be resistant or tolerant to a certain disease.

Most of the time, the population survive well. The population will likely decrease in size a little bit though.