The Seurat object contains scRNA-seq data from human lung multicellular tumor spheroid (MCTS). MCTS were formed by mixing A549, normal primary endothelial cells (HUVECs), normal primary human lung fibroblasts, and PBMC-derived monocytes at a defined ratio of 2:1:1:1, with a total of 20,000 cells per MCTS. 33,000 cells were used to generate single cell droplet libraries with Chromium NEXT GEM Single Cell 3' Reagent kit v3.1, 10X Chromium Single Cell Controller. Library size was determined by Agilent TapeStation assays and the concentration by Qubit Flex (Invitrogen). Libraries were pooled and sequenced on NovaSeq 6000 Sequencing System (Illumina), providing a read depth of >20,000 read pairs per cell according to manufacturer's instructions. A number of 4 samples was sequenced in 2 different batches, representing different donors of fibroblasts, HUVECs and PBMC-derived monocytes. A549 cell line was the same across all 4 samples and used with no more than 2 passages in between the 2 batches of scRNA-seq.