Xiao Zhang et al., in 2021, also provided vital information in the field of immunotherapy, namely that the anti-PD-1 response was significantly enhanced in tumors lacking both TAP1 and Qa-1b by knocking out these genes using CRISPR-Cas9 gene editing technology in a B16-F10 melanoma cell line and mice model [401]. Here, TAP1 is linked to melanoma.