Fungal Pathogenesis at the Host–Pathogen Interface: Immune Recognition, Evasion, Antifungal Resistance, and Emerging Therapies

Severe fungal diseases are an increasingly important yet underrecognized cause of global morbidity and mortality, with the greatest impact among immunocompromised individuals and populations with limited access to timely diagnosis and treatment. Disease outcome is determined by a dynamic host–fungus interface in which innate pattern-recognition receptors sense fungal cell-wall ligands and coordinate complement activation, phagocyte responses, and cytokine signaling, while adaptive Th1- and Th17-mediated immunity supports fungal containment and clearance. Pathogenic fungi counter these defenses through cell-wall remodeling and antigen masking, morphological transitions, capsule and biofilm formation, resistance to oxidative stress, complement subversion, interference with phagosome maturation, intracellular persistence, and colonization of immune-privileged sites. These mechanisms are deployed in species-specific combinations by Candida, Aspergillus, Cryptococcus, Histoplasma, Coccidioides, Blastomyces, Mucorales, and other medically important fungi, shaping tissue tropism, persistence, dissemination, and disease severity. Therapeutic control is further undermined by intrinsic and acquired resistance to azoles, echinocandins, and polyenes through target modification, efflux-pump upregulation, compensatory cell-wall remodeling, and altered ergosterol biosynthesis. This review integrates the mechanisms of antifungal immune recognition with common and species-specific evasion strategies and discusses antifungal resistance, emerging host-directed therapies, and vaccine platforms. Defining how fungal adaptation intersects with immune dysfunction and drug resistance may reveal conserved therapeutic targets and support rational combination strategies. Translating these insights into effective antifungal therapies, safe immunomodulatory interventions, and broadly protective vaccines will be essential to improve clinical outcomes and strengthen preparedness, particularly in resource-limited settings.