Table 4 Univariable and multivariable analysis of covariates for progression-free survival in the combination therapy and monotherapy groups

Age (≤ 70y vs. > 70 y)

1.09

0.59–2.02

0.79

1.11

0.65–1.91

0.71

Sex (Male vs. Female)

0.95

0.49–1.84

0.88

1.13

0.61–2.08

0.70

Performance status (0–1 vs. ≥ 2)

0.40

0.05–2.88

0.36

2.75

1.39–5.45

0.00

0.40

0.17–0.93

0.03

Histology (non-SQ vs. SQ)

0.98

0.49–1.98

0.96

2.27

1.19–4.32

0.01

1.62

0.78–3.38

0.20

Postoperative recurrence (Yes vs. No)

0.59

0.30–1.17

0.13

1.23

0.71–2.12

0.46

PD-L1 TPS (≥ 50% vs. < 50% or unknown)

1.88

0.90–3.89

0.09

0.47

0.23–0.99

0.047

0.99

0.39–2.49

0.98

The presence of irAE (Yes vs. No)

0.53

0.29–0.98

0.04

0.48

0.26–0.89

0.019

0.40

0.22–0.70

 < 0.01

0.38

0.21–0.68

 < 0.01