Matched blood and tumour samples from treatment-naïve patients with clear cell renal cell carcinoma (ccRCC, n = 8), nonsmall cell lung cancer (NSCLC, n = 4) and lung squamous cell carcinoma (SCC, n = 2; Supplementary Table 1) were obtained and studied using a bespoke 40-parameter mass cytometry panel developed to interrogate protein expression of TIGIT and CD226 across immune cell subsets, with a particular focus on T cells (Supplementary Table 2). Here, CD226 is linked to lung cancer.