I haven't checked any of the other 78 companies (not sure what the exact number might be), to which Merck has given Keytruda for research purposes, as to whether any of them have a Merck person working for them. That Dr. Robert Pierce is working for OncoSec as their CSO is no coincidence when one takes into account that Merck did their due diligence on all the possible companies.
Of course, Merck is large enough and has plenty of people which they could "plant" in all of the companies. Then, again, if they wanted to save time on their DD, they could have used the dartboard method or the staircase method to choose their "target" company(ies). ;-)
$ONCS