CD8A and neoplasm: However, an analysis of matched tumour samples taken from 78 patients before and 8 weeks after commencement of pembrolizumab within the SARC028 trial found that, among the immunofluorescence-based immune TME markers assessed, higher densities of activated CD8+ T cells and PD-L1-expressing tumour-associated macrophages (TAMs) distinguished pembrolizumab responders and non-responders [46].