STING1 and neoplasm: In particular, the cGAS-STING pathway has proven to be essential for the anti-tumour effects of anti-PD-(L)1 in preclinical models [13, 14, 226], and higher expression of cGAS and STING correlated with improved response rates and survival of MLH1-deficient cancer patients treated with anti-PD-1 [13, 14].