A synergistic antitumor effect has been shown with the simultaneous blockade of TIM-3 and CEACAM1, as well as CEACAM1 and PD-L1, on CRC models [36]. In the early stages of CRC, CEACAM1 inhibits tumor cell proliferation [34]. However, CEACAM1 is a diagnostic and prognostic marker in melanoma, and CEACAM1 is found in tumor samples and sera from patients with PC and is overexpressed in advanced stages of CRC, NSCLC, and other cancers [39]. Here, CEACAM1 is linked to pachyonychia congenita.