PDCD1 and breast cancer: Although breast cancer is considered less immunogenic, lower mutational load than other solid carcinomas, the synergism between anti-PD1/PD-L1 agents and chemotherapy has been supported via multiple preclinical pieces of evidence, particularly in the TNBC subtype (Adams et al., 2019a; Adams et al., 2019c; Loibl et al., 2019; Planes-Laine et al., 2019).