Ye Q, et al. - This research was designed to evaluate the link between programmed cell death protein 1 (PD-1) and indoleamine 2,3-dioxygenase (IDO) in the tumor microenvironment (TME) and in tumor-draining lymph nodes (TDLNs) among breast cancer patients. Findings demonstrated a positive association between the expression of PD-1 and IDO. Furthermore, it was determined that blocking both PD-1 and IDO pathways could present as an attractive therapeutic strategy in the treatment of breast cancer.