https://maths.anu.edu.au/research/projects/complex-cobordism-stable-homotopy
Complex cobordism & stable homotopy | ANU Mathematical Sciences Institute
Homotopy groups are extremely difficult to compute, and even the homotopy groups of spheres are only understood through some small range of degrees.
mathematical sciencescomplexcobordismstablehomotopy
https://mdp.ac/pce2020/abstracts/2403-Carmen-Rovi.html
Cut and paste invariants of manifolds and relations to cobordism
cut and pasteinvariantsmanifoldsrelationscobordism