In some embodiments, the invention includes a therapeutic combination of a phosphoinositide 3-
kinase (PI3K) inhibitor, including PI3K inhibitors selective for the γ- and δ-isoforms and selective for both γ- and δ-isoforms, and a Bruton's
tyrosine kinase (BTK) inhibitor. In some embodiments, the invention includes therapeutic methods of using a BTK inhibitor and a PI3K-δ inhibitor to treat
solid tumor cancers by modulation of the
tumor microenvironment, including macrophages, monocytes, mast cells,
helper T cells, cytotoxic T cells, regulatory T cells, natural killer cells, myeloid-derived
suppressor cells, regulatory B cells, neutrophils, dendritic cells, and fibroblasts.