[1] His contributions relate to improving diagnosis and utilization of less invasive medical procedures,[2][3] most recently as Global Chief Medical Officer at Guardant Health, Inc., a precision oncology company that developed a blood test replacing invasive tissue biopsies to sequence tumor DNA and improve cancer treatment selection.

[4][5][6] Lanman has worked in five different medical specialties, oncology, cardiology, endocrinology, pulmonology, and psychiatry, as well as historical ecology, and has authored or co-authored 130 peer-reviewed scientific publications.

During medical school and residency, Lanman authored journal articles in cardiology and psychiatry,[9][10] including a book chapter.

Atherotech offered a cardiovascular biomarker diagnostic known as the Vertical Auto Profile- or VAP-expanded cholesterol and lipoprotein test, to improve prediction of risk of heart attack and stroke.

[28] In 2005, Lanman joined a second preventive cardiology biomarker company, diaDexus, Inc., as Executive Vice President and Chief Medical Officer.

[32] After working in two companies to improve prediction of risk for cardiovascular events, Lanman joined Veracyte, Inc. in 2008 as Chief Medical Officer.

[40] Next, in a trio of publications, he and colleagues established novel physical evidence that the North American beaver (Castor canadensis) was native to most of California.

[44] In 2021, Lanman and colleagues published the results of an ancient DNA sequencing study of salmonid remains from archaeological excavations at Mission Santa Clara which extended the southern limit of the historical spawning range of Chinook salmon, 120 kilometres (75 mi) further south to San Jose, California.

[45] More recently, he proposed, along with the Muwekma Ohlone and Amah Mutsun tribes, restoration of tule elk (Cervus canadensis nannodes) to the San Francisco Peninsula and northern Monterey Bay regions.

[46] In 2023, he published, along with California Department of Fish and Wildlife (CDFW) and University of California, Berkeley biologists, a habitat suitability analysis which found long patches of habitat suitable for tule elk from Pacifica to the Pajaro River along the coastal and inland sides of the Santa Cruz Mountains.