CTLA4 and pneumonitis: For example, the combination of PD‐1 inhibitor and cytotoxic T lymphocyte antigen‐4 (CTLA‐4) inhibitor leaded to a significant increase in grade 1 to 5 pneumonitis compared with ICI alone28; the pneumonitis incidence rate in patients with EGFR‐TKI monotherapy was 4.59%, whereas it increased to 25.7% in patients received EGFR‐TKI combined with ICI treatment.29