From a Politico story on the U.S. Chamber of Commerce possibly gearing up to oppose politicians with certain pro-market stances in future primary elections:
Chamber spokeswoman Blair Holmes said the group supports “pro-business candidates in every election, regardless of whether they are a Republican, Democrat, incumbent or challenger.”
The distinction between pro-business and pro-market is important; for one example, see here. Never confuse the two.
And as Holmes correctly points out, the divide does not respect party lines. Both parties have largely pro-business leadership. It’s some of their upstart underlings, and much of the public, who are pro-market. Hence the Chamber’s primary threats.