CD274 and squamous cell carcinoma: Tumor‐specific antibodies secreted by B cells are thought to be part of the tumor immune microenvironment and participate in the tumor immune response.[107] Depletion of B cells promotes the growth of HPV‐associated squamous cell carcinomas, suggesting that B cells play a critical role in inhibiting tumor progression.[108] In an non‐small cell lung cancer (NSCLC) cohort with the treatment of a PD‐L1 antibody, elevated levels of B cells and plasma cells were found to be associated with improved clinical outcomes.[109] Using single‐cell RNA sequencing and BCR sequencing analysis, Kim et al.