TYMS and neoplasm: TS positivity, a marker of attenuated response to fluorouracil, pemetrexed or capecitabine,22, 23, 24, 25 correlated with MSI‐H, TMB‐H and PD‐L1 in many tumor types; thus, combinations involving fluorouracil, pemetrexed or capecitabine and immunotherapy are less likely to be of benefit.