The NIH Mentorship Modernization Act would require the National Institutes of Health to establish minimum standards for mentorship and career development support at institutions receiving NIH funding for early-career researchers, training programs, and fellowships. The standards would cover areas like regular mentor-mentee meetings, professional development support, career guidance, assessment of research progress, and minimum qualifications for mentors themselves. The bill directs NIH to build these requirements into existing reporting processes to avoid creating extra paperwork and to allow flexibility for institutions that already have strong mentorship programs in place. The law would take effect two years after passage, though institutions could voluntarily comply earlier, and NIH would have authority to provide supplemental funding to help schools implement the new standards, including money for mentor training and mentorship coordination. The Secretary would also need to periodically review and update these standards based on evidence of what mentorship practices work best.