Yes, one can run campaigns related to affiliate marketing offers / products, in Google Ads. For a better chance of success, the landing page must not indicate that it is made purely for marketing of an affiliate product or offer and the ad copies too must be appropriately worded. Lots (or some) of the offers / products related to affiliate marketing, are restrcited to run or not allowed to run in Google Ads (example : weight loss is restricted to run in Google Ads) and hence to run such niches, some (or many) advertisers cloak their campaigns.