Where does the comma goes into this sentence?

I think I would rewrite it this way:

"The World Health Organization, concerned with international public health, asked researchers to invest more time and money but the end results were the same."

You don't want to use "asked", past tense, and "was" present tense, in the same sentence that way.

Eric and Lewis rewrote your sentence, but didn't tell you where punctuation should go in the original. To be sure, some rewriting is required, but let's start with the original.

The semi colon following health is not correct. The semi colon is used to join two independent clauses (complete sentences) into a single compound sentence.  The first clause is not a complete thought, so it cannot be joined this way.

Rather, with one samle change, you have an appositive (some may say this instance is a paranthetical) that follows the sentence subject "World Health Organization". Appositives/parantheticals are enclosed by commas.  Move agency and add a definate article. Change the noun form for agreement. 

"The World Health Organization, the agency that specializes in international public health, asked researchers to invest more time and money, but the endless results are the same."