SFTPD and pneumonitis: Although the high SP‐D level was a risk factor in both NIVO + IPI and NIVO + IPI + chemo treatments as determined using the risk factors used in the multivariate analysis for each regimen, the F score and %DLCO were associated with only NIVO + IPI + chemo treatment, suggesting that existing lung fibrosis might have more influence on severe pneumonitis development when chemotherapy is used in combination.