Consistent with our findings, Bassez and colleagues [44] performed single-cell sequencing and proteomic analysis of tumor tissue from breast cancer patients before and after anti-PD-1 therapy and demonstrated that CD4+ T cells characterized by expression of T helper 1 (IFNG) and Tfh (BCL6, CXCR5) markers clonally expanded upon anti-PD1 treatment, suggesting that Tfh plays a critical role in mediating the therapeutic response to anti-PD-1 based therapy. The gene discussed is CXCR5; the disease is breast cancer.