Article 23.9 of the USMCA text as it stands now says:
Article 23.9 Sex-Based Discrimination in the Workplace
The Parties recognize the goal of eliminating sex-based discrimination in employment and occupation, and support the goal of promoting equality of women in the workplace. Accordingly, each Party shall implement policies that protect workers against employment discrimination on the basis of sex, including with regard to pregnancy, sexual harassment, sexual orientation, gender identity, and caregiving responsibilities, provide job-protected leave for birth or adoption of a child and care of family members, and protect against wage discrimination.
A Politico article on this provision says the following:
However, the Office of the U.S. Trade Representative, which led the negotiations with Canada and Mexico, made no effort to highlight the measure in a series of fact sheets issued after the deal was concluded. It also made only a terse statement on Monday, when asked about the measure.
...
The administration's quiet approach could reflect concern about pro-sovereignty conservatives "expressing outrage at a treaty that tells us how to define males and females," especially if HHS' rumored policy change goes forward and is seen as putting the U.S. in violation of its new USCMA commitment, said Bill Reinsch, a senior trade adviser at the Center for Strategic and International Studies.
"Shall implement policies" may give a bit of discretion as to what exactly is required; also, it's hard to imagine Canada and Mexico bringing complaints here (and if they did, there is still the issue of panel appointments being blocked). Nevertheless, it will be interesting to see how socially conservative Republican members of Congress react to the inclusion of this provision.
Speaking of progressive things that conservatives might hate, there are also rights for "non-national" migrant workers:
Article 23.8 Migrant Workers
The Parties recognize the vulnerability of migrant workers with respect to labor protections. Accordingly, in implementing Article 23.3 (Labor Rights), each Party shall ensure that migrant workers are protected under its labor laws, whether they are nationals or non-nationals of the Party.