Table 2.

Subgroup analyses.

	Subgroup	No. of cohorts	Univariate analysis HR (95% CI)	Heterogeneity test		No. of cohorts	Multivariate analysis HR (95% CI)	Heterogeneity test
				I2	P			I2	P
OS
Cancer type	NSCLC	6	1.62 (1.28, 2.05)	55.6	0.047
	Melanoma	6	1.78 (1.54, 2.06)	0.0	0.510	9	1.84 (1.34, 2.52)	76.1	<0.001
	Others	9	1.78 (1.48, 2.14)	74.6	<0.001	11	2.00 (1.50, 2.66)	68.0	0.001
Sample size	>100	12	1.58 (1.43, 1.75)	57.2	0.007	12	1.57 (1.34, 1.83)	56.2	0.009
	<100	9	2.99 (1.90, 4.71)	69.9	0.001	8	4.13 (2.20, 7.74)	64.9	0.006
Country	Japan	10	2.92 (2.24, 3.80)	0.0	0.706	8	2.01 (1.29, 3.15)	61.8	0.011
	USA	4	1.70 (1.45, 2.00)	41.6	0.162	4	1.38 (1.17, 1.63)	0.0	0.611
	Others	7	1.49 (1.34, 1.65)	66.1	0.007	8	2.50 (1.71, 3.66)	82.6	<0.001
ICIs	Nivo	7	1.98 (1.42, 2.75)	70.9	0.002	7	1.49 (1.19, 1.87)	50.7	0.058
	ICIs	7	1.69 (1.37, 2.07)	60.6	0.019	4	1.64 (0.89, 3.02)	80.0	0.002
	Others	7	1.73 (1.47, 2.05)	64.7	0.009	9	2.54 (1.82, 3.55)	67.3	0.002
PFS
Cancer type	NSCLC	6	1.39 (1.25, 1.54)	20.2	0.281	4	1.53 (1.22, 1.92)	0.0	0.649
	RCC	4	1.45 (1.02, 2.06)	50.5	0.109	4	1.30 (1.16, 1.44)	0.0	0.770
	Others					2	1.57 (0.75, 3.26)	93.0	0.000
Sample size	>100	6	1.32 (1.17, 1.49)	44.7	0.108	5	1.50 (1.19, 1.89)	57.9	0.050
	<100	4	1.52 (1.21, 1.91)	15.3	0.315	5	1.43 (1.03, 1.98)	45.5	0.119
Country	Japan	4	1.58 (1.32, 1.89)	0.0	0.416	8	1.36 (1.12, 1.65)	34.8	0.151
	Others	6	1.29 (1.17, 1.44)	47.0	0.129	2	1.68 (0.94, 3.01)	88.9	0.003
ICIs	Nivo	6	1.39 (1.13, 1.72)	47.7	0.089	6	1.34 (1.21, 1.48)	0.0	0.480
	ICIs	3	1.36 (1.14, 1.63)	49.4	0.138	2	1.11 (1.01, 1.21)	0.0	0.529
	Others	1	1.44 (1.21, 1.71)			2	1.85 (1.09, 3.13)	60.5	0.112