The risk of developing rash caused by PD-1 was found to be significantly lower than that of CTLA-4 only in the first-line therapy subgroup (OR = 0.51, 95% CI: [0.26, 0.99]; I2 = 87%, Z = 1.99, p=0.05; Figure 5(e)), whereas the overall effect was not statistically significant (OR = 0.73, 95% CI: [0.43, 1.22]; I2 = 86%, Z = 1.20, p=0.23; Figure 5(d)). Here, CTLA4 is linked to Skin rash.