the cluster of “ hes1 + macrophages ” identified in momac - verse showed the highest expression of the “ stab1 signature genes ” ( fig. 6d, e ). similar to stab1 + mɸ, hes1 + macrophages accumulated in tumours of lung cancer patients but also liver cancer patients and were suggested to represent a cluster of “ long - term resident - like ” mɸ with foetal - like transcriptional signature. in contrast, “ c1q ” mɸ from momac - verse, which have been described as lung alveol ar mɸ, had a high expression of genes unique to our tumour alveol ar amɸ ( from here on referred as “ amɸ signature genes ”, fig. 6f, h ). in the context of foetal lung, a rare population of apoe + mɸ, which accounted for less than 1 % of all foetal lung macrophages reported in ref., had a high amɸ signature genes score ( supplementary notes and fig. 6g, i, see “ methods ” ). taken together, our analysis suggests that tumour macrophages, especially stab1 + mɸ, exhibited a transcriptional signature reminiscent of mɸ during foetal lung development, suggesting that they have undergone oncofoetal reprogramming within the nsclc tumour environment. our study represents a large single - cell multiomics analysis of samples collected from treatment - naive patients with nsclc. we integrated scrna - seq data from nearly 900, 000 cells from tumour resections and adjacent non - malignant tissue from 25 treatment - naive patients with spatial transcriptomics to build an atlas of immune and non-immune compartments in lung cancer. luad and lusc, the two most common nsclc subtypes, exhibit markedly different prognostic outcomes and have shown potential for subtype - specific therapies. despite similar cell - type composition, we observed significant differences in the co - expression of several icis and inhibitory molecules between luad and lusc, highlighting therapeutic opportunities. luad samples frequently expressed tigit and tim3 ( havcr2 ), while in lusc we found the putative ici cd96 - nectin1. while different advanced clinical trials targeting tigit, including in patients affected by nsclc, are ongoing, progress on tim3 and cd96 is more limited. a first - in - human phase - i study evaluating the anti-cd9 6 monoclonal antibod y gsk6097608 as monotherapy alone or in combination with anti - pd1 ( dostarlimab ) started recruiting patients only recently. taken together, our data suggest that luad and lusc patients might benefit from specific immunotherap y targeting icis as tim3, tigit and cd96. the tme plays a crucial role in modulating the population and behaviour of mɸ. we found that, compared to the adjacent non - tumour tissue, tumour resections harboured a lower proportion of monocytes but a higher proportion of monocyte-derived cells, such as mo - dc2s and anti-inflammatory mɸ, suggestive of an enhanced monocyte differentiation in the tme. the prevalence of anti-inflammatory mɸ, including stab1 + mɸ, exhibited an inverse relationship with the abundance of natural killer ( nk ) cells and t cells in the tumour environment; and the nk cells within the tumour exhibited reduced cytotoxic activity. our results are in line with the recent findings that the removal of tumour cell debris by lung mɸ leads to their conversion into an immunosupp ressive phenotype, consequently hindering the infiltration of nk cells into the tme. mɸ with elevated levels of tumoural debris were reported to upregulate genes involved in cholesterol trafficking and lipid metabolism, a characteristic shared with anti-inflammatory mɸ in our dataset. as a result, they downregulated co - stimulatory molecules, cytokines and chemok ines essential for the recruitment of cd8 + t cells, therefore becoming more immunosupp ressive. among the mɸ population within tumours, we also identified stab1 + mɸ that exhibited the highest level of immunosupp ression markers. these stab1 + mɸ displayed a gene expression pattern akin to that of foetal lung mɸ and demonstrated a modified iron metabolism, marked by the increased expression of genes associated with iron release in the tme. therefore, we hypothesise that stab1 + mɸ might play a crucial role in supporting tumour progression by sustaining the increased iron requirement of highly - cycling tumour cells. in a subcutaneous llc1 lewis lung adenocarcinoma model, mice lacking stab1 expression in mɸ, tumour growth was diminished. this outcome was attributed to a shift towards a pro - inflammatory phenotype in tam and a robust infiltration of cd8 + t cells within the tme. stab1 + mɸ displayed a transcriptional resemblance to camls, which concurrently expressed genes associated with both mɸ and epithelial cells, and exhibited copy number alterations ( cnas ) similar to those found in tumour cells. stab1 + plays a pivotal role in facilitating the adhesion and engulfment of apoptotic cells by engaging in a specific interaction with phosphatidylserine, supporting the hypothesis of a strong interaction of a mɸ with a tumour cell in camls. in previous studies, camls were identified by immunoflu orescence in the peripheral blood of individuals affected by various solid tumours and were proposed to facilitate the dissemination and establishment of circulating tumour cells in distant metastatic sites. here, we report their presence in multiple tumour resections, based on a combination of a compound gene expression signature, tumour - specific copy number alterations and physical proximity to tumour cells, as evident from visium sections. taken together, our comprehensive dataset allowed identifying a multitude of molecular changes in the mɸ population of the lung tumour microenvironment, which will help pave the way for the development of therapeutic strategies against nsclc. tissue used in the research study was obtained from the papworth hospital research tissue bank. written consent was obtained for all tissue samples using papworth hospital research tissue bank ’ s ethical approval ( east of england — cambridge east research ethics committee ). human tumour and adjacent background tissues, collected from the edges of the lungs, were obtained from 25 patients following tumour resection. human healthy lung samples were obtained from two healthy deceased donors. both healthy samples were evaluated by an expert pathologist to exclude the presence of malignancies. the human material was provided by the royal papworth tissue bank ( t02229 ), in accordance with the hmdmc human tissue act sample custodian form version 7. 0 ( uk nres rec approval reference number ( s ): 08 / h0304 / 56 + 5; hmdmc 16 | 094 ). nsclc ffpe tumour blocks ( n = 2 ) used for validation of stab1 + macrophages with akoya were obtained from 2 different donors and purchased from bioivt ( ex - asterand bioscience ). informed consent form ( icf ) and institutional review board approval letter ( irba ) were obtained for all tissue samples. sex was assigned ( 15 male and 12 female patients / donors ). sex - based analyses were not performed due to the limited sample size. tissues were kept in cold complete rpmi medium ( rpmi [ invitrogen ] supplemented with 10 % fbs [ sigma millipore, catalogue number: f9665 ], 2 mm l-glutamine [ life technologies, catalogue number: 25030 - 024 ] and 100 u / ml penicillin - streptomycin [ thermofisher, catalogue number: 15140122 ] ) until dissociation, which was performed on the same day of collection. single - cell suspensions were generated as follows: tissues were placed into a petri dish and cut into small pieces of 2 – 4 mm and transferred into a 1. 5 - ml tube containing the digestion mix ( complete rpmi media supplemented with 1 mg ml collagenase iv and 0. 1 mg ml dnase i ) and minced using surgical scissors. minced tissues were incubated for 45 min at 37 °c and vortexed every 15 min. digested tissues were passed through a 100 - μm strainer into a falcon tube prefilled with cold pbs.