As you all know, Google recently treats the no follow link attribute, Bing Corresponds about how they treat it. An Authoritative person from Bing says that they always consider no follow link as a hint and making their own decision whether to trust over the link or not.
Google always took no-follow attribute a directive for ranking crawling and indexing where bing always took it as a hint by following their own decisions. Now Google considers it as a hint for ranking factor and will take it as a hint for crawling & Indexing From March. Bing always considers it as a hint.
Check out what an Authoritative person from Bing said in his tweet:-