Who Does WHO (World Health Organization) Work For

Is there a requirement the WHO takes only the betterment of the world into consideration with their decision and judgements?  I mean, will a regulatory overseer come in and put the WHO officials in jail if they cater to the nation's political leaderships instead "doing good" for the whole world?Remember when Trump threatened to not fund the WHO for not following his agenda. So WHO is set up to cater to their members, not necessarily their populations  Especially for the great powers who fund most of the WHO. You see how important china is to the WHO?