Although they had relatively high expression of the cytotoxicity markers such as PRF1, GZMA, and GZMB except GZMK (Figure S8f,g, Supporting Information), NK cells in SCLC‐dominant subpopulation were most likely exhausted as they had high expression of TGFBR2 and low expression of KLRC2 (Figure 6f). This evidence concerns the gene KLRC2 and small cell lung carcinoma.